Hey, you're on the right direction. The idling issues is a classic Volvo P2 ETM problem. There's a trick to pick the right one. Used ETM, working one, though used, is not issues at all. Just put in the right one. Just remember, Turbo ETM to Turbo ETM, Non-Turbo to Non-Turbo ETM. Your original is a 'White labeled' ETM for Non-Turbo. Go get a same one and it will work. "Yellow Labal" ETM is for Turbo models. But you need to be sure the new ETM you put in is working fine from the yard. Takes a little swapping but it's the right way to fix this issue. No software updates required. Plug and play only. DO NOT go get one of the Xemodex units cause they too have issues and not reliable at all in my book. Cheers Dude! you're doing great !

The volvo v70 will always have some issues, but it is worth it anyway and if you sell it you will always regret it. Trust me. Volvo gets under your Skin, in a good way. Take care. From Sweden 🇸🇪.

To diagnose voltage drops i would start by connecting connect 4 temporary thin cables from the dash to: *the battery positive pole *the alternator, *the big screw on the fuse box under the hood fuse box *to a free fuse position in the fuse box near the door (phone is usually free) Then connect an volt meter to a pair of the cable to see the voltage drop between them. A negative value means you need to switch the polarity. If there is a voltage drop between the alternator and the positive screw at the fuse box under the hood you have bad connection or wire between alternator and fuse box. Same applies to the other cable pairs. You can do the same between ground points too to check for bad ground connections too. Just remember the low amperage fuse in line with all the cables at the different sources to prevent damage in case of short to ground. Also remember to not use amperage mode om the multimeter. Good luck fellow volvo owner :)

Hi i hope you can see this message. Regarding your idle issue there is one more thing you should check and that is not known to that many people, even Volvo entusiasts. In your right side-mirror there is an sensor for the outdoor ambient temperature. This sensor talks to the ECM (it will not throw an error code if its not working) And if its not working either the MAF or lambda will try to compensate and you will end up with an irregular idle. Open the right door panel and located the cables going to the side mirror. I believe there is two connectors (one for hte mirror it self and one for the sensor), unplug them both and look for corrosion. If there is no corrosion then look for damage and with a multimeter check the continuity. If you still dont find any problems then the sensor might be damaged. Change the sensor, but its much easier and less time consuming to just change the side mirror. Hope this helps. Sorry for my English.

I see someone else suggested the Volvo brand MAF. This also fixed it for my 06 V70R. Don’t give up. I enjoyed watching this the series!

I had a similar frustrating problem as you on my 1999 2.4 na five cylinder Volvo S80. It would idle fine until it got hot, then it would intermittently rough idle and sometimes stall. But when the fan came on or under bonnet temperature dropped a bit, it would be okay! I replaced the ETM with the Sacer contactless kit, and it felt better, (revved cleaner) but it wasn't cured. It turned out to be the inlet VVT solenoid. When it gets hot, either the electrical circuit inside the solenoid stops working (check out a Diagnosedan video with a BMW with an hot idle problem ) or the sliding rod inside the solenoid casing (which expands faster than the casing) has varnish on it and sticks in the casing. The first thing to try is removing the electrical connector from the solenoid, to see if the idle settles. My engine only has VVT on the inlet, but the principle would apply on the exhaust as well if you have two. All through working this problem out, I never had any trouble codes and the EML never lit up. It drove me crazy for about two years until I worked out there were two problems occurring at the same time, and because the symptoms were caused by two failures, no one could diagnose it, not even my local Volvo specialist. Hope that sorts it, let me know!

It’s definitely fixable. Plenty of cases where even the specialists can’t figure it out and this is coming from a Saab guy. I’d look into installing an OEM MAF if you haven’t already. You’re close! I recently purchased a $1000 9-3 Aero XWD and after a ton of work it’s now mint. A car should and can work as intended, even at $800.

You have to program that new throttle body because it's a different part number one and that maybe still won't work and check your drivers door wireharness and the light switch.

18:16 OK Dude this is the clue. When you said that the issue happens on hot days. My old Toyota had the exact same issue. On really hot days, when the engine was full temp from driving, and then I would park it and let it cool for an hour. When I'd go to start it up again it would stumble. This is clogged EGR dude! Take my other advice and do a thorough cleanout of your ENTIRE intake system -- but I realize you're tired so do that after. Start with the EGR system. Make sure those lines are clean and flowing well. MAYBE replace the valve, but just clean it to start. AT THE END OF THE DAY YOUR PROBLEM IS CARBON ALONE. Not electrical, although good call getting a spec alternator, 120 amp is very questionable. These cars came with either 140 (or 160 amp I think for the winter packaghe). I upgraded to 160 and an H8 AGM battery cause I just don't want to flim-flam around. Take my advice dude. EGR, it can do strange things on hot days with a hot engine.

Find the right replacement ETM, if yours isn't already the right one. Look up the proper part number. As far as I know the yellow labels were for both atmospheric and turbo models and signified they are the new one from the recall. They changed the color so mechanics could quickly see if the car needed the recall or if it was already done, but I may be wrong here. The first years of the P2 the ECM failure codes are a crapshoot and you will have to do actual diagnosis to find out what the root cause of your problem(s) are. You are on the right track and checked/found/fixed most things already. What I would be looking at next is possible bad contacts at the ECM connector (I have had to reseat ECMs several time and clean the connectors and such to get gremlins out of these cars) and measure "reference voltage" at the ETM to figure out if you have a voltage drop on there. Oh and by the way, the ETM on some P2s takes it's ground connection from the engine and not from the top of the wings.On the turbos it's somewhere close to the starter....

@WheelemVerb - Check that serpentine belt! It's on backwards. Ribs always go towards the ribbed side of a pulley. This will result in less contact surface for the belt if not put on correctly allowing slippage.

l have the same car, v70, 2003, metallic champagne with Euro style headlight wipers and 17" double 6 spoke rims. The car behaves extremely well except for unstable idle from high velocity to a sudden stop. The only solution l use is to depress the clutch and pop it into neutral while braking. Fully stop the car with clutch still engaged. Release clutch and the car immediately restores to correct idle.

Happy that guys like me exist, you went my path . IT IS THE ETM. AND YOU DONT NEED NEW ONE. you need SACER sensor. Also check map hose , and maf sensor be sure it is good one like "Hella",

A lot of helpful comments down here. I would love to see another video, was waiting on this one for a long time. You are so close, don't give up!

Many good suggestions. For the oddball possibility, the sensor on the power steering pump. There are a million reasons why it shouldn’t be the sensor but it is one thing that increases RPM with load. If the sensor wrongly detects load it is increasing RPMs when it shouldn’t. It’s a long shot. In the words of Joe Dirt, “keep on keepin on”. You will get it.

In the UK there's a bad idle/rough running evap purge valve solenoid at cost 30 pounds

Ive owned a 03 xc70 and had the same exact issue. I went through 3 mafs all of which were bosch and none fixed it. The moment i put the volvo Maf in, the came to life again and stopped its stupid idle.

Had the same issue, changed the MAF and loads of stuff in the end, disconnected the alarm and the idle issue was solved

Woa I’m so shocked but absolutely stoked you have a channel like this! You’re a dude way more after my own heart than I initially thought!

please find the solution! my Friend and I have the same issue with the same car. Volvo in Germany has erased the model out of their system! they have to use Bosch to read the codes. I am begging you don`t give up find it and you will be the most beloved V70II youtuber!

Your Volvo is fixable!! Remember the motto of the crew in the movie "Galaxy Quest." NEVER GIVE UP. NEVER SURRENDER." ❤

Fantastische Volvo video’s. Complex probleem wel, nog veel succes met de diagnose!

Really like the look you've given the car! Great build! You should be proud, it's a credit to you!

i had the same problem , loping idle on hot engine, you said "especially on hot days". i traced it to the cooling fan in the ecu box. its located in the air hose from the cabin to the ecu box, directly under the power steering reservoir. you might want to read the duty cycle , compare between engine cold and hot. make sure its not restricted, supply air comes from the cabin which it would help cool the ecu box if the a/c is running to provide colder air. if you get no joy, see which cyl is misfiring with your live data setup, should be easy after that. my 2004 with 225K miles runs and idles good, don't accept defeat. It will idle fine once you track it down.

I would check the vacuum lines by the engine mount near the firewall

You deserve waaay more subscribers. Amazing quality content!

This was a glorious watch in spite of things not working out ideally man, so rad to get to go through the motions with you even if they didn't end up resolving your issue. I still have hope that it ends up working out though ahah even if you're over it!

Good luck man, hope you get to the bottom of it. I have almost the same car, 02 NA manual. One owner, maintained by one Volvo specialist mechanic for 20 years. Bad news is I brought it to him about 6 months ago with a similar hiccup in the idle and it’s still cursed. Started with an ETM rebuild by xemodex, sent back to them 3 times, and finally tried a virgin unit programmed by Volvo. Seems to be fixed every time then it will randomly have a fit some morning. BCM, CEM checked or refurbished by xemodex. Everything else tests good and if it starts and runs, you can drive it no problem. But… Something keeps intermittently crashing the CANBUS, I.e. cluster dies, abs/brake failure warnings on the dash and the idle goes to shit until you turn the car off, then it won’t start again without disconnecting the battery. I’ve basically given up on it but it’s become my mechanics White Whale. He needs to know wtf is wrong with it so he’s been poking at it nights/weekends. Last I heard another Vo specialist was going to borrow a $40’000 oscilloscope/signal analyzer and bring it to town some weekend.

Even tho this car didnt work out 100% I’d say it came a very long way from where it started and the knowledge and skills you’ve gained are really what matters anyway. Can’t wait to see more Volvo stuff in the future! I just picked up the cheapest manual C30 on the east coast so you’ve inspired and I’m gonna start making some videos about the whole process of fixing it up and making it the ultimate daily/weekend warrior :)

dunno if it helps, but I dug around on the volvo forums and found a couple of people saying they fixed similar warm idle hunting issues by resetting/relearning the TB to ECM - disconnecting the battery and letting the system discharge for awhile (or just touching the pos & neg cables together for a short time), then step on the brake pedal (without key in the ignition), put the key in and turn it to position 2, and from outside of the car (with key still turned to position 2), shut all the doors and then reconnect the battery (negative cable first). sounds like madness, but it's a low-effort/expense shot. good luck!

Got the exact same car and boy it's a joy to drive. Keep it up

keep that beauty , we all have our faults , perfection does not exist

great content, beautiful car! thanks for sharing 👍🏻 greetings from a Saab enthusiast from overseas

With some cars, when this issue with the idle happens, you have to "re calibrate/programm" the throttle body.

I have had about 7 Volvos and have done most of the maintenance myself. I would have picked the ETM also. I had a similar minor issue on an S70. Almost had it rebuilt by a company on the West Coast due to the cost of a new one. It is critical you have the correct one. There once was a long Blog about the ETM on one of the Volvo sites...lots of complaints. I finally just cleaned my very carefully, especially behind the butterfly valve and it was almost OK.

I got an 04 v70 with the D5, common problem with age is the brakebooster seal leaks vacum from the white cylinder where it enters the cabin. i got it fixed temporarily with thick ass grease around the cylinder and old seal. you buy new seals from URO parts, there are several variants and you can only tell which is correct by removing the seal on your booster(number is on the seal) its a massive bitch of a job the first time. makes all the difference in the world in a diesel engine. its a rarity in a america for sure, but thought you would like to check it out. good luck!

It'll be something to do with the o2 sensor and whatnot you had to futz with. Some mismatch between the sensor, the header and what the computer is expecting so that it is never quite on the right plan coming down to idle. The idle fiddliness will be the ecm hunting for a setting that works.

I had an issue with idle, but it was worst. The car won’t drive at all, so I’ve been told by the person who fix ETMs that I have two options buy new and program it at the dealer or send mine to him and he will change the throttle position sensor. Those ETMs are programmed for each car specifically so you can’t just get used from the junkyard. So I sent mine it got fixed and after that car was driving perfect. Also this issue shows up around 200000KM (kilometres) mine went bad at 208k. It is my experience.

My ‘99 Miata has a similar issue. 2/5 stops at a light, the revs plummet from rest (around 1200rpm) to 500-400rpm and then goes back to rest after a few seconds. If I have the Heat or Air on in the car it will do it less (my guess is there’s more power being used). But that’s about as much understanding of the issue I have. Forums say that it’s an “it is what it is” issue. The car hasn’t stalled on me so I try not to get worried about it. Thank you for the great video! I look forward to seeing more.

NO WAY WILLEM. You’re a big reason I got into photography in 2019-2020. Since then I have grown my skills in photography a lot. Grew away from watching youtube and creating my own things. I also have got a 01 V70 2.4t since then too haha. Cant believe this channel just popped up on here. I also had the same problem with idle and changed the pcv and put a new throttle body in. Idk if it fixed it though I haven’t driven it much since then. If you do fix this though i’ll have to check the same things on mine. p.s. you might want to update the ecu using the vida software so it knows you put a new throttle body in. idk if you have to do that with the NA engine though.

Don’t give up! I had a 1998 Pontiac Grand Am that had a similar idle issue under certain electrical loads. Sometimes it would actually stall out. Turned out it was a problem with the main computer, swapped it out and bam it ran perfect until I scrapped it.

I know on some older Audis of this era have a rubber ring seal around the air intake that can come unglued causing air to flow into the engine unchecked and it can cause idle issues

Try replacing the bosch EVAP purge valve ontop of the radiator, underneath the airbox ducting. If that valve is stuck open/malfunctioning it will cause the idle revs to drop low. If you apply 12 volts to the valve, it should click. If it does not, then its stuck and will cause idle issues.

No idea if you’ve already done this, but several times on a few of my previous vehicles (admittedly, not Volvos but other euros) that weird idle problem like yours was caused by a faulty temperature sensor. If I’m guessing correctly it only happens when you’ve had the car running and warmed up? If that’s the case then it’s definitely something to look into. A faulty temp sensor can cause all sorts of problems like running too rich, inconsistent idle etc etc. A good way to test is by bridging the connection between the temp sensor connector (the fan will run permanently on) and if nothing changes then I’d swap it out!

Had the same idle issue with my Volvo v40 2003 - root cause was a bad fuel pump. Resolved the issue.

That's it I'm buying a S60R. I've watched enough of your videos. I've owned an XC90 D5 I miss that thing but I wanna go fast. Good video btw really enjoyed it.

The white labeled ETM you took off was original, the yellow is a revised version so it’s good you did find one. I would pull the ecm fuse for 15min to reset fuel trims so the ECM/ETM can relearn. It’s possible a small exhaust leak or dirty O2 sensor is throwing off the fuel trims enough that it’s causing the stumble trying to find the right AFR to idle. I’d take a look at that data

Your videos are cool. My first car is an 2006 xc70 and I really like it. I noticed after doing some exhaust repair that the car now revs a bit high for a few seconds on cold starts and then releases to idle. I read that volvos do that for to meet emissions. I don't know maybe an o2 sensor or something could fix your uneven idle. Cheers

I honestly still wouldn’t be surprised of the problem would still be the ETM. They are known to go bad, like you said. Maybe you could try it with a known good one. Preferably one of a car with the same engine code and MY, that gives you the best chance of it playing nice. Luckily they are easy to swap out on the non turbo models.

dunno if i commented this on the last video or not but check your VVT(s)!! i had play in the exhaust VVT on my R and that way cauing my idle issue. car would stumble randomly but mostly at idle. easy to check, pull the cover off and give them a tug, shouldnt move in or out at all. Exhaust VVTs go out in these cars commonly.

Love driving my 2001 V70 T5! Second owner. Purchased 14 years ago with 110K. Now 179K. It had new automatic transmission installed at dealer due to porosity problem on valve body shortly before I purchased it. Would love a manual version but have the next best with the tiptronic. I'm like you... I turn my own wrenches. Last year, sent cem to Volvo electrics specialist outside of London, England for repair. While gone replaced entire pcv system, new alternator (with clutch), all coolant hoses, all sensors, banjo bolt on intake (had no ball in it!), MAF, fuel pump, rebuilt Volvo ETM (lucky snag off off Ebay!), rebuilt ac compressor, new ac condenser, new ac hoses,and new ac orings, rebuilt power steering pump, spark plugs, both O2 sensors and radiator. AC works great! Replaced muffler and resonator with practically new ones I cut off from local LKQ. Purchased like new driver's seat cover years ago off of Ebay in anticipation of replacing (T5 has it's own design) and replaced it myself. It is such a FUN car! Punch it and go! Like you... I learned alot! Best to you on your next project and always!

I’m pretty sure Volvo has a technical journal regarding replacing the ETM and its wiring harness going from ETM to the ECM. It might apply to this

Mine had the exact same problem with the uneven idle, sometimes the throttle body even stuck to some random position. I replaced the throttle body angle sensor with magnetic sensor and that totally fixed the problem with idle. Also the clutch pedal switch was faulty on mine and that disabled cruise control, replaced that and it's been since a wonderful car to drive everyday.

dont give it up man, you can do it. I would check if the connection between the alternator and everything else is in perfect condition, maybe change the wires as preventive maintanence and dig into the voltage drops. Often guys that remap cars can help you out with finding out these issues and maybe you will want to get that v70 remapped for some extra power, but i know not many people work on volvos, at least in my country

hey buddy, I have a 2003 S60 2.4i and I have the same issue going and popping up again and again since I have the car, which is about 7 years now. It is idleing rough e.g when I get to a red light, then it is smoothing up. At some point I think in 2002 there was a change in the ETM supplier. They changed from Magnetti Marelli to Bosch. I already have the Bosch unit that is said to be better, but still not perfect. Every time I am going to a Volvo specialist repair shop for a service, I ask them to clean the ETM. It solves the issue for a while, then it comes back in 5-10 thousand km-s again. Once my Volvo specialist said that he has never seen an ETM unit on these cars that work properly for a longer time. I would give the ETM one more try, it sounds totally identical to my problem. I also know there is a company somewhere in Germany who are specialized in renewing these MM ETM units. Let me know if you need the contact. It is no wonder both of the units that you tried were faulty.

I have the same v70 and same issue, check out the brake booster, as from when i had bought mine, the brake booster was leaking causing the vacuum to lag and stutter like this. Hope all is well, love the videos!

Just a suggestion which may resolve the issue: check the lambda sensor. I had similar issues (varying idle when hot) and the problem was a bad lambda. Also check its connectors and cabling. By the way, i enjoy a lot watching your videos. They're sincere and don't require a fully equipped workshop to do the job.

Volvo v70 and s60 from 01-05 had problem with throttle body but volvo fix it when the facelift came around -05. On my v70-01 it worked when i cleaned the throttle body and switched the gasket but i know people who needed to switch the throttle body and use a computer to program the new one. I remember that it was a special brand that volvo used for throttle body that had so much problem Greetings from Sweden 🙂

I hate that it didn’t work BUT at least the gx loved for another day! We gotta see some videos on that!!

Voltage drops on grounds and power wires, somewhere you have a weak or compromised connection. Could be a damaged or corroded wire or connection in the harness parasitically affecting power to the throttle body. Your're gonna need schematics with connector location info, and a scope to watch as you test wires, and watch Ivan (Pine Hollow Auto Diagnostics), Mario (Super Mario Auto Diagnostics), and Bernie Thompson (Automotive Test Solutions) videos to figure it out. Most shops do not have techs with the skills and equipment to fix stuff like this. I use to buy unfixable cars just to fix and sell. I was never even the best at it, I know guys way better than me, but it just means it's not the car that's unfixable, it's the people working on it are incapable, DIYer nbot included, don't give up, it's probably something so simple

What's next? Another wagon? Adventure vehicle maybe? 👀

Чувак, ты молодец! Отличная машина и отличный проект!

I had the same problemen with my s60 2.0 t. Disconnected the battery for half hour. Solved the problem.

Just to throw this on the comment pile . . . I have a '96 850 wagon NA. Was having idle issues, and the fix was cleaning the idle air control valve. The valve did not look especially dirty, but, when I cleaned it, the idle issue was gone.

If you want an amazing wagon - is300 sport cross. They don’t come manual but swaps are common, super fun car. I’ve had two manual sedans

It sounds like when I used to work on aircraft. Sometimes to diagnose electrical problems, we would just start turning on systems that drew a lot of power. There was a chart that showed the power consumption for everything, so we would just find the highest load systems and turn them on at the same time. Sometimes things only start to show their issues when you put a lot of stress on them.

As a s80 t6 owner who struggles with my own problems its so amazing how complicated these things can be for such old cars, im struggling with no boost during acceleration and a strange noise follows it its most audible at 2-3 thousand rpm and im going to have the boost pressure sensor fixed today to see if that fixes it

I also got a v70 p2. The MAF has always been a problem. Also the air intake valve control solenoid. Barometric pressure sensor A just popped up. Greetings from Sweden. Yours is way nicer!

Thanks for the video. You'll figure it out. Let the solution find you!

I really know nothing about cars but I do want to share a kind of similar situation, my Smart 450 had an engine replacement and after it the clutch actuator would just slip the car into neutral when going in reverse, wouldn't go into gear, all without any codes or errors popping out. Turns out the guy who did our engine replacement did the wiring either in the wrong order or ''not as neatly as needed'' plus the way he mounted the cooler actually damaged an electrical component. After that was fixed the car never had any electrical issues again.

My 2001 Volvo V70 2.4 NA manual (on BCs, and R brakes too) has the exact same idle issue. And I went through everything too. Ultimately, I’ve also decided it’s easier to put a bit of pressure on the pedal at a stop and ignore the problem than it is to keep chasing it.

Maybe upgrade to an H8 battery? That "bigger bucket" fits perfectly if you want to run some extra electrical loads.

I've got an 04 S60R and I love the thing, but it needs about $6000 in work, including major rust repair. Probably going to end up parting the car out since I can't put that much into it. The engine and transmission are in amazing condition, but the angle gear is going out, all the suspension needs to be redone and so on.

As a fellow perfectionist, don't give up! You're so close to making it mint and truly dailyable. Btw whats up with the dash pad? Never heard of a dash cracking in these cars

well. a volvo is a relible car. but it isnt easy to fix. my dad has a v70 from 2006 but it only runs on 3 of the 5 cylinders. Also tried a lot of things but that car WONT run good. we are about more than half a year further. so keep the hands up if you want to fix it. love the video`s. Greats from the Netherlands

Check the ground cable from the starter motor,it gave my V70 some rough idle😊

I would say that your experience with your car is never overlooked versus a guy who works daily with volvo's. You drive your car weekly and you are more under the hood of that car than anyone else. I hope you get that idling problem fixed dont lose hope.

There's a sensor connected to the clutch pedal under the dash. If it's out of spec or faulty, the idle could act up. Faulty one disables the cruise control. And idle correction when depressing clutch at a stop n go . Values in resistance for sensor is out there on forums. Good luck!

This is a voltage problem. There should be a relay that switches between short and long cooling circle. It might be faulty in the way, that it does the job but messes up with ECU. It might not output the right voltage (still switching the circle though) and thus ECU could start compensating it with rpms. Fairly cheap and not obvious thing to try. It took me 2 years to figure it out in my 2005 fiesta back in the day. Your parts are probably fine. The car just makes wrong decisions. Most of the time it's electronics related, which is a nightmare to figure it out.

Check the wiring on the throttle body conector.

great video, voltage spikes and dips is screaming a possible cem issue to me. It's a common thing to break and give very weird issues just like this. Although I've personally never encountered this exact problem. I assume there's places that inspect and repair them in the US as well.

volvo gang. mooie bak.

You could be off a tooth on timing. On the 04 R I picked up this was the case despite no check engine light or warning in VIDA (it should throw a CEL). I don't think this NA has a vvt hub on the intake, but it might on the exhaust. Watch my most recent video about the black s60 R if you're curious how I diagnosed this in VIDA.

pls dont give up. its a car, then its fixeble.

Try disconnecting fuses to se if there is one connection that is problematic, understand your frustration. I had an Audi that left me with a sower taste, now I stick mostly to land rovers 😊

I have the same 04 and hope to do the manual swap one day! R rims and all 😂

it's a MAF problem mate. For sure! Change to a new one if you can and the problem will be solved!

Take the original throttle body apart, make sure everything looks right in there...

2000 P80 V70 B5244SG2 (Denso Ignition System) Manual owner here with exact same issue, goes down to 500 rpm and picks itself up just before you'd expect it to stall. Alternator charges okay, no visable vacuum leaks, unplugging the MAF does nothing weirdly, I feel it's running a bit rich as well, thought about replacing the lambda but according to the ECU it's within spec... wondering if it could be to do with the VVT solenoid. Typically this is a sign of the ETM going out and there's different software versions to do with the specific modules (programmable through VIDA) But yes, moral of the story, you're not the only one, Greetings from Scotland

Wires, Once car is warm and problematic start pinching, wiggling wires going to TPS ( throttle position sensor). You can get short finders etc but just my guess. Looks identical to my TPS and issues had. Was a faulty wire. Could also replace the TPS but my bet is it's a wire

If Volvo's use the pcm or an external module to control field current in the alternator id look there next, that much voltage sag looks abnormal for no more load than the system should be under operating the windows. The voltage dip may be unrelated too. If the maf is dirty or a poor quality aftermarket then the normal rpm dip (few dozen rpm) for electrical load may be exacerbated by large swings in fueling from incorrect maf signals when the closed loop fueling control is trying to chase a moving target.

Yeah I just had a look online so that's what I came up with I'll see if I come up with anything else

I owned a white Volvo s70 for 23 years. I had the same problem with low idle and sometimes stalling.

We need a video about the subie!

You should ask David Bello what he thinks could be wrong with your Volvo V70. He would probably know what it could be. He's a longtime Volvo enthusiast and KZfaqr. I believe he's living full time in California now. If you haven't met or heard of him already then you should definity check him out on KZfaq and other social media platforms. He's probably one of the best Volvo guru resources there is.

My friend some time ago had a problem with alternator, he got misfiring at idle LMAO, from alternator. When he put down belt from alternator car worked fine, replaced alternator with new and car works fine without any issue. It was S40 2007 with 2.4i 170hp. In some cases after ETM replacement reload of software is needed in it. I don't remember but you checked PCV system if it works? It can cause high idle.

Have a Look at the Hose from intake manifold to pressure sensor on the Radiator. My s80 did the same, only when Hot, a small cut You couldnt even see ,wiggled the hose and IT went worse😂 greetings from germany

not sure if it was off camera but the smoke tester wasn't actually building any pressure in the clip where you showed the gauge

It certainly looks like an electrical problem - obviously.. But on my S60 I have a "problematic" idle, not as yours but similar and it depends on the AC unit starting to go bad I think. As long as the AC is enabled the uneven idle is there, when I turn it off it normally goes back to good again. Of course, I believe all cars can probably see a voltage fluctuation when enabling or disabling functions/features in the car, but that should be pretty minimal, but what other car and software can you measure it "this good" in? Maybe BMWs, I don't know but I haven't seen this available in any other cars, so its kind of hard to compare I guess. But you get like 0.4 Volt in fluctuation as I read the graphic chart, I doubt that is really the issue.. If you haven't looked at it, maybe the AC compressor or maybe the power steering pump? I'm far from any pro at this, I have never diagnosed anything like this, but I just want to give my thought on it and I really want you to get your car fixed - plus I want to see a video on it 😋

I had a software update for the ETM on my s60 and that worked