I really wish I would remember half the stuff I watch. Absolutely love this video.

Eric, thanks for taking the time to talk at length about the vacuum leak and manifold pressure. I watch these videos for one reason, to learn. Watching you thoroughly explain how Baro, MAP, and MAF work together with RPM & LT/ST FT's was just what I needed to see. I've yet to see another video on YT where someone explains it so well and in a real world application. One of your best teaching videos yet - Well done Sir!

I'll say it again with the risk of repeating myself : BEST AUTO REPAIR AND DIAGNOSTIC CHANNEL ON KZfaq!!!

One of the few auto repair channels I will contribute money to. You do a wonderful job filming,staying out of the scene and explaining the why. Love all I have learned. This is like a school.

It's people like you that will save us. Thank you!

Wish there was someone like you here in my area I could trust to do the job right. Do most of the work on my vehicle myself because when I take it in and tell 'em what I want done it comes back and I'm disappointed with the work that was done. Your videos are well done!

There is not many videos that deserve a replay, but this is one of the exceptions.Every effort was made to simulate as many permutations as possible .There was 3 variables contributing to the skewed outcome and it made for very interesting viewing.There was no effort spared to fully complete the video and it has to get 12 outta 10.

The dealership version of this video. Tell Customer they need O2 sensor, Put in O2 sensor, charge 850 dollars. Not even address the leak or anything else. if that doesn't fix it, charge for more things. Thanks for the great information. learnt a lot from this video. All your customer are lucky they have you =P especially this one. Holy cow, that car needs to be under coated lol.

Your a natural teacher. I really appreciate the time it takes to do these videos.

Low MAF #s + high fuel trims = vac leak. If you noticed, the before cleaning and after #s on the MAF varied by about .75grams. After it was cleaned and with the vac leak induced, it only read about 3.5 to 3.75 at idle, and that's too low. Anyway, this is a really good real world demo on how several small things, lead to big problems.

SMA University - Avoca, NY Campus. Top of the line.

“Can’t plug a plug into a plug...although some guys try” lol

Very good vid Eric and glad you showed all the different variables with the vacuum leak versus the MAF. Excellent work!

In all my years of auto repair (20+ years, I have just a couple years ago started dabbling with driveability. And not fully understanding the data that is seen, and having no one that can truly explain the data and the normal/abnormal results and WHY..... now I have a much better understanding if at least fuel trims. And look forward to my next driveability challenge!! Thanx again for a wonderful channel!!!! Peace!!

I really appreciate the time you spend on teaching us. Especially the diagnostics. I wrench at home and this is a valuable recourse. I feel I need to donate to the patreon account now. Keep it up. You make America great again.

ERIC, you really are a good doctor off fixing cars u have an excellent way and approach and very intelligence how to find if there is a problem connected or not to the first one. learned lot here thanks for all ur time and effort cheeeers my friend.

I have owned that same OTC fuel injector tester since the 1980's. Still works good. They were manufactured right in my home town BTW...Owatonna ,Minnesota

Great video Eric. Learned a LOT. Not sure how you can make any money though fixing things on a car when it came in for something else, unless of course the owner OK'd the labor. And I know you can't bill for the video time, which makes it all that much nicer that you do this for us to learn from. YOU are the BEST!!! Tomorrow I change the F-150 front differential oil and you know how much FUN that is....I need to find someone with real TINY fingers!!!!

What an outstanding video, well done! Live graphing with the scan tool makes vacuum leak detection so much easier, and you didn't even need a smoke machine. Best O2 sensor video ever, ha ha.

As long as I keep watching your vids. I don't need a scanner , thanks Eric o

How did mechanics ever repair cars before all the electronic diagnostic tools? Oh yeah, with the best diagnostic tools there are: eyes, ears, nose, hands. That’s how my grandfather did it, and he was self taught. I learned a lot from him, but as cars became more computer than car, just makes it harder for a shade tree mechanic. Regardless, this is one of the best channels out there. Still learning a lot from Mr. O, as well as VGG.

Hi Eric, My daughter’s 05 Tahoe (which she dearly loves incidentally) has a money light issue. I’ve taken it twice to a friend who operates an independent shop. They clear codes and have run smoke tests (twice) with no determination of the source of a leak which we suspect might be causing the codes. My daughter’s ex-husband being somewhat of a useless mass of carbon, tried fixing the truck himself a couple of times and ended up replacing the downstream 02 sensor, but of course he cheaped-out and bought a Chinese knock off to save about ten bucks at Auto Zone. He claimed to have had a buddy of his who knows what he’s doing diagnose the problem. That’s how he came to the conclusion that the downstream O2 sensor was the culprit. I can’t have my granddaughters out there riding in a truck with issues which might at some point cause a breakdown on I-95. Additionally the truck has failed state inspection now, and she can’t get her registration renewed until the problem is fixed. So I’m done playing around with it. I ordered new upstream and downstream O2 sensors and a new MAF and will put all three in this week, then I’ll clear the codes using my cheap tool and see what happens. I also found the vacuum leak on the truck in this video to be interesting. Given its location and fact that it’s not easily seen, it could be where the leak on the Tahoe is and might not have been detected during smoke tests. So I’ll be checking that hose on her truck for sure. If these don’t do the trick, I’m driving it to NY and leaving it with you so you can give it a try. Its only 4 or 5 hours to your lovely area and I don’t care if it takes you two weeks be able to get to it. I’ll leave it with you to get it fixed the right way. There are a few other things you might be able to help with too. Lucky for you this truck lives in a more southern state and hasn’t been exposed to the road salt you fellas suffer with up there. So rust won’t be what you typically see on NY vehicles. I’m just tired of playing around with people who are supposedly skilled and trained experts, but who don’t know much more than me (a retired old sales guy). I know these people are well intentioned but it seems to me that they don’t have the skills necessary to properly diagnose and repair these systems. The dealerships are even worse I’m afraid. They hire youngsters fresh out of tech school and then set about training them how to increase revenue for the dealership. BTW, this isn’t a rant, so please don’t mistake my attitude here and get the idea I’m a snobby jerk that you don’t want to deal with. I’ll be nice I promise. So if by chance you happen to see my comment here, you might be hearing from me in a few days. Thanks, BK.

Eric I had to stop working at late 40s and am 66 now. But watching you and learning you make me miss it working I mean. Keep it up and the best to you and your family.

utilizing the internet, connections made within, and retesting. this is why i watch you.. awesome channel, this is the one i like.

I've been watching your site for over a year now and am very impressed with your ability to troubleshoot and find wiring problems. I've been a farm mechanic, shade tree mechanic since 1977. I really enjoy a challenge and electrical troubleshooting is my favorite. But I get lost at times in my work. But I never give up. When it comes to watching your Shows, I love the in-depth explanations and information you pass along to us. It's greatly appreciated. You are a gifted person. I wish everyone in the automotive industry could be as and honest as you. Great job, keep up the good work.

1-2-BBQ indeed! Great video sir! Taught me a lot in this one when it comes to the Fuel Trims and such. I appreciate the info, especially since that 4.3L is almost the same as my 5.7L... Mine just has two extra cylinders. Thanks for the video, the brake cleaner, and hold on to that bag... That darn cat is somewhere!

This is *the* best video if anybody wants to understand fuel trims and catalytic converter. Bravo!!

Great video, learned a lot! I appreciate you taking the extra time. It makes your channel the best learning tool on automotive issues in my opinion. Thanks Again.

One day, when I grow up, I wanna be this guy with the sweet little shop and all the toys needed. One of my two favorite channels to watch, the other being AvE. Both of which are very intuitive and their one liners are second to none

sorry about your scan tool troubles, but I am glad to know it's NOT just me! Half the "new" scan tools I try are broken to begin with

Awesome Eric!! Love your saying "If I can do it, you can do it."

Wow that was enlightening. I drive a 03 astro cargo van for our company and the hvac hose broke. I just lived that way for about 2 years. I was alarmed that such a seemingly primitive actuator for creature comforts was vacuum in a modern car and not a motor. Oh well what do I know. I'm a computer guy.. You mentioned that the hvac is the last of the vacuum driven accessories. So it is primitive. Also It didn't dawn on me that the hvac hose as small as it is could have an adverse effect on fuel economy running rich. My van has been sucking gas about that long. I just figured she's old. I replaced the hvac hose this weekend. So I am looking forward to the vents working but perhaps better fuel economy. - This is a rockin channel. I want one of those windows hand held based scanners. - just cool.

I also love the non-swear words 🤣 what the thunder ❤️.

WITH THE HEART AND HELP OF MS.O!

Please more s10 vids! 2.2 or 4.3s! 2x4 or 4x4 they are all wonderful vids you have but i want to learn everything about these since i have multiple in the family!

Thanks for explaining fuel trim, I must of read forums and watched 30 videos, and still not understanding it. Tested out your knowledge on my wj, found the leak, and now idles perfectly. Can’t thank you enough for making these videos. Great story teller and teacher, keep up the great work, thanks again bud.

Another block buster movie there Eric ,top notch !!! Nicole and I were watching your vid and she noticed there doesn't seem to be any females commenting on how much they like your vids. Nicole just loves your vids- like big time. Nicole thought if you did the odd vid in yoga pants you'd attract a lot of female techs to your channel and maybe even Bruce Jenner as well :) Steve.

I failed so many emissions tests over the years in WA state, and had to get the waiver by spending $150.00 on "repairs". The shops never replaced anything as far as I can remember and it never left the shop running any better. I finally got through all the years of emissions. It is now too old to be one the list. (Free at last. Free at last) It began to get to me, over the years so as I had some time off from work, I decided to devote some time to trying to get the thing right, without taking it to a shop. With the help of a parts guy, I learned how to turn my key three times to the on position, and watch the blinking "check engine" light and count the numbers of the blinks and read what codes they were, going to a Chilton's book, and found I had 4 codes, IAC motor, MESP sensor, TPS, and EVAP circuit (unplugged connector), and 02 sensor. I replaced those 4 parts, and WOW, smooth power I never had, and no more 9" diameter black soot stain on the concrete anymore when I start it up, and the fuel mileage is way up. So, as each of those 4 parts I replaced, simply screwed in and were all well under $100.00, (one of them only $11.07 with free shipping) Why is it that through all those years, none of the shops ever replaced anything? Did they just want to have it sit in their shop for an hour or two while I sit there, and then charge me the $150.00? All I got for that money, for the most part, was "Well it's not running like it should, and I don't know why", or after I told them I thought it was running rich because of the black soot, it was "We will check it out.", or sometimes it was, "It's simply not worth it." Do you want a waiver? So I will be watching these videos.

Great lesson as always, Dr O. As always I learned a great deal from a master!

Hey Eric, Great video (as usual). I know this is a older video (can't believe I hadn't seen it) but I learned a lot. I've been focusing on understanding fuel trims, and between you, Matt and Paul I am finally getting it. Again. Thank You so much. Merry Christmas and Happy New year to you and your family...

I've been watching your channel for a few years. I am not an auto tech or in the auto repair industry. But after watching your videos, and especially this one, if I were young again, and was choosing a career I would want to diagnose and repair automobiles. Excellent video! Many blessings to you and your family.

love the music intro Eric all the way from Scotland, great shop u created there bud, I am in Awe off to tool range, lifts and great family office

I don't think most of your shops would have went the extra mile to get the fuel trims sorted out , great example of how to keep em coming back

I have always wondered how to read those fuel trim numbers after watching this now I know. Thanks for sharing 👍👍👍👍👍

Yet another great video. Another good lesson in thoroughly diagnosing the problems. Way to hang in there and getting the job done.

Great vid Eric. I always learn something when I watch your vids. Keep up good work.

Surprised it didn't have a code with the vacuum leak and the Dirty maf sensor Causing the huge Fuel trim corrections making the system Rich because it was Way to Lean nice work Eric O @SouthMainAutoRepairLLC

I am not a mechanic, but I wonder how this guy makes a living with such perfectionism.

Great video!. This past summer I went to change to change passenger side downstream oxygen sensor on my 98 Ford Explorer V8. Pulled the front seat, middle console, carpet, and access panel only to find out that I had the sensor for the other side which had too short a connector. Drove over to Advance Auto and got the right one to finish the job.

Nice. I love watching the graphs although a bit mind boggling. I start thinking about the physics classes I've taken but have to remember theory isn't exactly the same as reality, lol. I learn more and more through you, Eric. I really love the brake cleaner trick looking for vacuum leaks. Thanks for taking me along on another adventure.

Eric, thanks for the great tutorial on vacuum leaks. I'm running into a similar problem, both short/long term fuel trims are really high. Your tips here have given me some real direction, and I will try the things I"ve learned here

Ur very thorough mechanic. Thanks for being so detail oriented. Kudos

Another excellent high-detail diagnosis vid, thanks Eric!

No disrespect intended to ANY Erics but this is why I watch and follow THIS Eric and not the other Eric because the technical aspect is VERY INTERESTING and showing your diagnosis is EXACTLY what I want to see, not fitting roof rails to any car....that is most definitely a DIY task, this is NOT...Again no disrespect intended, i do drop in on the other guy occasionally when hes doing something interesting (to me) but RIGHT HERE IS WHERE THE ACTIONS AT BABY.....Nice Show Eric O.....hey that rhymes :¬)

Advance Auto will sell you the right part. Occasionally!

Eric, your channel is one that taught me NOT to fall into that "ignore the engine light, it'll go away" trap. I know what mine is on for, but recheck it every so often to make sure things don't change for the worse. (We have limited funds for car repair atm, and yes, I keep my fluids checked.)

How is it that I don't have a test light?!? Sheesh. Thanks Eric O. for another educational and entertaining video!

I actually learned a lot. I've got a solus ultra but don't use it enough to be proficient with it. Thank you for the lesson. I also like how you don't just throw parts at it. You test it out then verify the repair.

I love how the thing was nearly out of gas. Gotta love guys that bring them in that way!

Awesome Video, I watched every minute of it and learned a LOT. Thanks for all the time and work you put into your videos for us.

Fantastic video really gave me an insight, here in the UK we don't do things like drive cycles etc and euro spec cars are much more forgiving with check engine lights but will still pass an emissions check, videos like this really help me to understand how to get my cars running as well as possible, thanks!

New subscriber, watching and learning. I just watched you channel on o2 sensors and vacuum leaks. This was very informative and I really appreciate your video. As with all the previous videos, binge watching. I find them very educational. Thank you again for all you do!

Thumbs down are either trolls or haters. Neither are worth our time. Many modern vehicles sound like there is a vacuum leak when there is not. Great job, again, on a great video of just running down a step by step process of diagnosis and repair.

Best learning video You have ever recorded.Third time to watch it ,and see something new each time. Thanks!!

Eric you look like a real scientist in those safety glasses there! Awesome process of separating the variables and going back to test them separately to show cause and effect. Looking forward to the Dakota case study that you mentioned at the end :) I'll bring my injector tester and Verus along in case you manage to burn up your new one too lol

HI ERIC THANKS A LOT FOR YOUR TIME TO EXPLAIN THINGS IN A WAY DUMMY LIKE ME TO LEARN FROM YOU AND UNDERSTAND. YOU ARE AWSSOME . THANK YOU

nice work Eric you coverd all the good stuff , that otc fuel injector tester badass tool .

Great video Suggestion: remove your hood draw string. The AC belt can grab it if you instinctively look down at the fan.

This one I added to my saved vids. Fuel trims understanding took a big leap today on this one. My favorite vid of yours to date. U teach I lurn > learn.

Great video, finding a vacuum leak, isn't about listening for it, it's about going through the technical data, and educating us all. I learnt a lot about fuel trims and how o2 sensors work. Cheers man, keep up the good work.

Great video. The long term fuel trim increased at idle after you cleaned the Air Mass Meter and reproduced the vacuum leak. From memory it was around 17 before and 25 after cleaning the Mass Meter. Dirty Air Mass Meter tend to give negative fuel trims at idle in the range of 5 to 8 per cent. . I think that is the explanation for the increase in fuel trim after cleaning the Mass Meter and reproduced the original vacuum leak. The negative fuel trim of the dirty mass meter was compensating a bit for the vacuum leak given a lower fuel trim. This may explain why some dirty mass meter do not show negative fuel trim at idle. A dirty mass meter combined with a vacuum leak will show positive fuel trim at idle.

As always, excellent work and video. Thanks.

those darn s-10's from that era always have that same hose fail, as well as all the other vacuum hoses. Looks like they used cheap rubber or something. My uncle's HVAC was not working due to that vacuum hose. I only replaced that small part b/c it looked to me like i had to remove the fender to get to the rest of it.

Well! I think I learned a few things from this video. Thanks South Auto Main... Now you made me into a Brake Clean freak instead of water... i always like to go the cheap way first.....lol.

I used to work in the field, and I've seen a bunch of these videos. And this technician is topshelf.

Very instructive video Eric! Thanks a lot for sharing!! Looking forward for the Dakota video!!

Great job Mr. O! I've been trying to figure out why my 08 Chevy Uplander minivan 3.9 V6 is not getting a little better mpg than it is, about 5 to 6 mpg less than it should be. This the third one I've had it is a flexfuel this time. Oh and thank you guys for helping learn how to use my hand held scan tool even if HF it works good for what is. Uplander is a work in progress.

You're a hell-of-uh mechanic Eric O! Love the channel.

Yet another great video. Hope the Maxisys gets fixed. I'm about to order mine.

I love that you tested the wires going to the sensor before just replacing it 👍. When I see the hose loose underneath the hood I imagine like someone trying to see if you are a scammer 🤣. Good job man 👍

Hey there Eric O. Paul M here from way out west coast in Kalifornia. Huge fan of your channel. I really enjoy watching your humorous and methodical approach to solving mechanical issues. I have tried searching for information on Vct oil control systems and cam phasers specific to the Hyundai Santa Fe 3.5 v6 Lambda II MPI engine. My wife took hers in for an oil change and minor service. It just clicked over 100k on the odometer. The very next day, she fired it up and the CEL lit up. It put my OTC code scanner on it and pulled the following docs, P0014, P0366, and P0341. Theses are all pointing to an issue with the cam phasers being out of spec due to oil flow through the vat solenoids. There is lots of data on these Vct systems on the Ford 4.5 engines, but virtually nothing on the Hyundai. I am surprised due to the sheer number of these SUVs on the road out here. After reading all the complaints on the forums about these Hyundai and Kia engines blowing up and bursting into flame, I would think that someone such as yourself would have already encountered this issue and made a video for your channel. Right now, we are awaiting parts, the oil control solenoids, but I have a sinking feeling that once I replace those, I could still have an issue with one of the four cam phasers. Note, the engine has been relatively problem free up to this point. We have always changed the oil at proper intervals and done all the factory recommended maintenance as well. If you have any suggestions, pointers or just some moral support, that would be appreciated.

over an hour long, but it doesnt seem like it. fantastic information. thank you for doing what you do. i learned a lot.

Awesome video Eric very educational! I bought a 2001 s10 brand new got about 210,000 Mi on her. I say around 2011 I lost all my HVAC blend door controls. Long story short wound up taking off the face plate to the dash to get to the actual control module that lets you change fan speed, vent selector dial, and temp control. After doing all that and going to the junkyard and getting a new part still had no vent Direction. Wound up going to a shop and just asking a mechanic and he said there's a little nipple on the driver side fender that lets you change the blend door. Few years later same thing happened except this time I had to follow the hose all the way around the engine up underneath the front bumper and replace the hose and reconnect it to the air pump. But the line that goes to the end side fender nipple is the one that always rots out. Another thing I did to the vehicle just recently was replaced my lower manifold gaskets and upper manifold with the felpro kit and updated my fuel Spyder. Thank God for KZfaq channels and mechanics like you that help us save a lot of money and teach us how to fix our vehicles!!! 1 2 bbq

Glad there are people like you to go the extra mile to make things right 👍.

Great Video! I could hear the vacuum leak with my head phones on. Sorry to hear about the electronics issues, still seemed to champ through it!

Brake clean for the win !

Glad I found your channel, great info and diagnosis

Great video Eric as usual but do you employ someone purely to hammer on metal and gun wheels on and off for your videos lol :)

Another Great Video! You should be an instructor! Thankyou also for the relationship part between the MAF and fuel trim percentage numbers. The vacuum leak was icing on the cake. I got a good learning curve a few years ago with fuel trims, vacuum leaks and the Ford WDS (before the IDS). The problem was the step up or step down size of the PCV hose on a 2003 E350, V10. I had to learn HOW to use the WDS (Won't Do Shit) and THEN figure out the fuel trim problem. Actually, Good Ole Brakkleen found the problem. Then I learned the WDS. Used correctly, it was a great tool, when it wouldn't lock up! Then came IDS. Thank God for small favors!

helping a junior tech a couple weeks ago replace an a/f sensor broke the hex right off the sensor,nothing left but the treads and sensor in the hole that sucked on a 2010 ish Mazda not even an old rust bucket either,great video

On the slim chance that you never receive a "thank you!" for these videos, you are certainly receiving one from here! Between this video and the one that you did replacing the injectors on a C4 Corvette, I've found my way out of a pretty severe mental block and I have only you to thank for it!! Happy Easter my friend and thank you Once Again!

Good one ! Once chased a vac leak after changing the spider on my 4.3 for a week it idled high enough to push the truck down the road at 50 + the long term trim was maxed out and pushed the lows into the teens turned out to be the O ring around the spider housing rolled over and allowed the slightest leak not detectable by "WAIT FOR IT"!!!!!! brake parts cleaner also found out the updated spider housing was .050 shorter than the stock CPI housing long story short little vac leaks can have big affects also!

Very eerie, Scotty K. just popped up in the lower right corner of the play next screen. Good video btw.

Had the same leaking line that goes to the vacuum reservoir but didn't know where it went so I just plugged it. Will get it straightened out this weekend. Thanks!

Thank you so much, every time!Watch your videos I certainly learn something new, once again thanks.

Man I wish you were close to my location because you would definitely be my go to guy for work on my vehicle. Unfortunately mechanics as good as you are hard to come by. Keep up the good work and I wish you all the best and thank you for these videos, you're awesome.

Hahaha I am absolutely loving the brakeclean intro noise.

ha! I like that, "thing is a toilet." Good video as always.

sorry to hear about your scanner woes, I love my autel the only complaint I've had is I can not get it to auto read VINs. Keep the vids coming strong work !

"Total weaksauce but we made it cool". T-shirt tag line for SMA repaired vehicles. Give one to every customer. ;)