those are the reason I service my own car from suspension ,driveline to engine!!I don't deal with dealership!!I saved a ton of money

I purchased an 04 Silverado with 123,000 miles on it a few years back. It had misfire codes galore in it, all I used was a simple code reader no data stream-just codes. Removed the spark plugs, 4 were original the other 4 were of different makes including an Autolight??!! Replaced them with the correct AC Delcos, ran better still had a bit of a misfire. Chased it down with LP around the intake, yes sir intake gaskets leaked as well also found the knock sensor wells were full of water and corrosion in the connectors for the knock sensors. Got all of the parts at NAPA, including the knock sensors and connectors. Been running like a champ ever since.

You are a very good mechanic, you were very clear to understand and I learned a lot.I had a random misfire while driving, I changed the spark plug wires, that was not it, changed the spark plugs, that was it. Now I have random misfire at idle. I'll do what you did in the video that gave me a lot of things to check. Thank you so much for your video, you are a top notch mechanic.

"Ghost misfire?" Spooky!!!! Must be a dealer technical term........lol

A previous misdiagnosis handled professionally by the Car Doctor - you're a class act! Hopefully, you've got a customer for life.

I sure do enjoy these videos!! The thoroughness of your work makes us shade tree guys get a little more dangerous with each watch. Thanks for taking the time to do all of the work. I know it takes a lot to edit and upload, but more importantly, to finish your regular work too! Keep it up ;) I actually bought the Topdon “Elite” scanner for ABS codes and it actually worked. That things is really great for what it is

Incredible.......a set of new spark plugs vs pulling the heads for a valve job. Is it any wonder why people don't trust dealerships? Good job nailing this one Tim.

No money for a dealer to just change spark plugs. And we used to think it was the small garages that would rip people off. My how things have changed. Good honest job Tim.

Went in the drive through just fine.. .came out engine shaking.. rotten egg smell..but after first gear it wouldn't shake so bad...changed fuel filter..egr valve and spark plugs/wires...all needed to be changed but didnt fix the problem...took it to the man of reason...turns out bad spark plugs are hard on your $45 IGNITION COIL.... $70 labor...engine saved--priceless

Another WIN for the independent shop.Good find!

You're a good guy Tim. And it goes without saying, a credit and a blessing to your profession. As well as your customers.

Come on tim you haven't seen those hoseless compression testers yet lol, great video i like how fast and efficient you execute your repairs

I can relate. I fixed a Prius that had been towed to a Toyota dealer. They couldn't get it running and told her she needed a new HV battery. I cleaned the 12v battery terminals and it fired right up. Just a little oxidized was all. It had drained and wouldn't hold a charge so I cycled it on the charger 5 or 6 times and now holds a charge.

Handy little scanner to keep in the glove box!

Thanks for the video Tim. Been a mechanic since 1983 and this does not surprise me one bit. I never worked at a Stealership but I have heard of many horror stories such as this.

I have a autel maxicheck pro and it only cost me 179.99 I love it. I'm a diy guy that also buys broke down vehicles and fixes them. Bought the tool to bleed abs and it worked great. I use it for mostly chevys

This is why I don't go to dealers. Thanks for this great video!

Thanks Tim, you’re awesome good guy God bless you

Excellent video. You've convinced me to take my car to the local trusted mechanic instead of throwing parts at it. Subscribed and liked. THANK YOU

One reason I'm trying to learn automotive repair is because I got ripped off at a dealer. We still have to pay they're crazy price for parts but we can take control of the labor and misdiagnosis costs. Funny you mentioned a vacuum leak causing a no start in cold weather. My 1998 5.7 Chevy is doing just that. Wow, that plug was toast! Basic visual check just saved him a lot of money.

Great Great work and video! I was just watching some videos about misfires and ran across your video and I'm very glad I did. I have a autel 439 scanner and its OK for the price. Your topdon scanner is great, I follow your link and purchase it today and can wait to use it with mode 6 function. Thanks for the video.

Once again I couldn't have done a better review on the tool myself. Man those plugs are toast! A very good diagnoses and fix. Good job Tim.

Thank you for this video you are so honest old school mechanic very hard to see one like you you really nailed a coffin good job by the way I like the OBD scanner I might buy one

Great video. Thank you using a obd scan tool that is more available to a novice at home do it yourselfer, showing how easy it can be to diagnose a check engine light.

Nice fix car doctor my thinking was going toward maybe a plugged up low flow or restricted flow on injector but yes I would have checked those plugs first I used to sit there and look at plugs and try and figure out what going on in cylinder but after being a scanner danner guy for a while I kinda moved away from it you showed me a little old school diagnostics does work but those plugs were pretty obvious they were too fouled causing a weird burn at certain points probably because all that carbon would heat up creating a little hot spot for pre ignition i was also thinking of how to check floating or sticking valve with scope that's so cool gotta do a clutch tommorow on my toyota that got stolen and they completely fried the clutch

Hey Tim, Brian from Idaho. Thanks for letting my kids take a photo of you and I. You have the best handyman channel I've seen and appreciate you sharing your knowledge with all of us! Again. Thanks for the upper/lower ball joint video for the 2500 Dodge diesel and all of the tool recommendations as I bought them all & they worked great as promised. Having a guy like you who is willing to teach us shade tree guys is a Godsend. Brian

Hey Tim how are you my friend thank you very much for your hard work to give accurate diagnosis... I know I ask a lot of questions lol but just a really quick one today ....What are fuel trims and what is the reading I should look for on it

Thanks for the update!

Frickin laziness there partner! the world needs great mechanics like yourself! Good Job...

Excellent video, very informative....Experienced old school mechanic. Just goes to show you that you can't trust anyone today. Good mechanics are very hard to find, but this guy was freakin great!!! Like he said, stick to the basics, fuel, spark, vacuum, compression, etc.

Simple repair for a simple problem!!!! Good solid diag ! Keep them coming.

A really great video. And a great job at fixing the truck. Like the guy said below. The only thing sticky was the dealership's fingers. I wish I knew how to read those codes and figure them out. Tim you are an excellent mechanic. I sure wish I lived near you. I would bring all of car repairs to your garage. Thanks for sharing your video. Have a blessed new year.

Great video Tim. Like you said stick to the basics. The dealership should be ashamed of themselves. Love the channel man, thanks for all the great videos!

Keep It Simple Student. The kiss rule prevails again. I am a rookie tech and these videos are valuable. Thank you very much for sharing. I can never find guys willing to help me so I have to learn everything on my own and I work in the industry. Hopefully one day I'll find a job where I can join a positive team and we can help people the right way. You have my subscription. Great job

They would have charged that guy over 2k for that job they said it needed ...thanks for the great job explaining...

Nailed it! Its amazing what fake problems the dealers come up with and tell the customer in order to take advantage of them.

Happened In my 2002 honda random misfire ,changed coil and plugs injectors compression test nothing happens.Changed the EGR valve and everything is now back to normal.Thank God.

Chevy Dealer told me the same thing about my cylinder 7 misfire, it was a ghost code. Cylinder 7 had a new plug, spark plug wire, and coil. According to the dealer it had "perfect" compression.

We're trying to track down this issue with my son's 01 Blazer with a 4.3 Vortec. Will recheck the gaps on the plugs. Thank you very much for the video!

hey man, great videos on this problem. i was wondering, with your experience, do you think these misfires are happening because of low test gas being used? also do you think using 91 to 94 octane will prevent these problems right from the start. thanks and keep up the great videos!

just ordered that scan tool. displays a lot more info than my current obd11 thanx for the tip ! ^-^

Great video! Thank you.

Thank Doc for info awesome!!

Nice job Doc as always!

A relative compression test with a 10-15 second crank may reveal a valve issue…don’t know if you do in cylinder testing but that would bring your diagnostic skills up a notch !!

Thanks Tim u the man helped me fix wife’s car major brownie point

Thank you Tim. I just subscribed to your channel on the other videos. You are da'man!!!!

I had the same code pulled my plugs and that was it thanks (160000 miles on my silverado original plugs thanks)

Awesome fix sir.

Thank you DR .....helps a lot on my 04 envoy po302 code

Thank you for your nice details video

Stealership says a lot of b.s. Nice diagnosis & thanks for the demo of the inexpensive scan tool.

I wanna get that Scan tool.... You are very easy to understand when it comes to diagnostics and explain in problems and codes with the vehicles....

I just did mines i change the ingiton coil pack the one that was misfired and the ingiton modulator that sit under the coil pack but it still had a lil misfired but when i change the the spark plugs wires the misfired was gone but i had brought some cheap wires last time and the only last 3 months

Never take ur vehicles to the dealer unless its under warranty still. They will 9 out of 10 times try to rip u off. My sister is the service manager of a competing dealer where I live. And she says when new techs are hired they are told in orientation to always upsale every job. I mean tell them they need work that's not even needed. Dealerships are a joke outside of warranty work

Alot of times at least with the older Chevy's the Vortech cap (especially) the 4.3L from my experience. The V6 has a plastic distributor and it can have issues. I kept getting the P0300 code I replaced the cap 3 times and it kept melting away and bringing terminals,once the rotor got warped. I replaced the distributor with an aftermarket aluminum one from Summit Racing and the problem was fixed. I also have a 5.7L vortech in my other truck. The cap melted through in that one once bridging the cyl 1 & 6. Replaced the cap & rotor & it's fixed now. Seems like alot of people have these issues from what I've been seeing on KZfaq. Also I've seen some chafed wiring harnesses on the Chevy Astro van.

Imagine a garage with you sir and Brian from Fordtechmakuloco....what a kick ass combination.!!

thanks tim

Great vid, straight to the point and explained in layman's terms You are a good man, do you think it could be the same case for my jaguar x-type misfiring? Thank you. From Ronnie in beautiful Scotland.

Update, i still have the p0300 code. I bought that scanner but somehow it won’t read on my 2010 Silverado. I don’t know if I have to update the version or what. Any help. Plz comment

great thanks for you.nice video.

Nice to see an honest mechanic, that dealership should be shutdown.

what were the symtoms in this truck? i got the same code today. truck running fine though. autozone guy told me maybe it needs fuel injector cleaner

i have a 1996 sc1 saturn, 324,500 miles and it runs great, i just bought a 2004 impala ss, its a gas hog and has a misfire, and other problems, so i fixed everything besides the misfire and ill fix that too, but once i fix it, its going bye bye, I'm going to buy a 1993 saturn in a few days with 68k miles, its like my two door and ill drive both of them, i love the older saturns, there amazing on gas. i also did buy a mercedes c230 recently, good car but ill give that to my dad.

Great video! I’ve changed the spark plugs & wires & still have the p0300 code. I even changed the catalic converters. & still have the same problem. Any ideas of what I’m doing wrong? Do I need to clear the code. Any help would be useful.

I got one for u went to change motor mount jacked up one side now I have misfires mainly on drivers side and can not figure it out ran great before

I have a 2006 highlander hybrid with a VCS Trac off check engine and brake light on any thoughts

Mostly for viewers, Car Doctor obviously knows this: You can (sort of) estimate compression by looking at cranking voltage with graphing meter. Normally this is only done only in cases where spark plugs canm not be reached (transverse V6 minivans etc). No reason to skip physical compression on a Chevy. How the dealership has to "wait for compression test results" is beyond me.

Clitch in The Matrix at 18:57 😆 Nice job. Old guys rule!

you new all along , they were going to be railroaded , your a good man

Just found this video working on the wife's 05 Caddi. Good info here Tim. My OBD scanner is throwing me P0300 codes, Time to check plugs. I'm not to quick to blame the dealerships or the small shops. Its' more of "it's hard to find good help these days". There is a lot of incompetence out there, The more knowledge you have the better off you'll be . keep up the good work Tim. By the way, I'll trade ya an '05 Cadillac sts for that Solus even up, Ill deliver ........ Yeah I know, I wont hold my breath.... -Tom

Excellent video

Man you're awesome. I wish you could diagnose mine. 00 Silverado z71 5.3 with p0300 random misfire. Already replaced intake gasket, 02 sensor, plugs wires and coils and still isnt fixed. Any ideas? 263k miles and has always ran strong . Good oil pressure and no tapping. Also the check engine light doesnt flash at idle. Only driving at 2k rpms and above

hello did you not need to remove all plugs to check the compression? I was told it was required. I am a simple do it yourselfer

Had the P0300 code on my 2006 Ford Explorer the engine was running rough put in a bottle of Lucas Injector cleaner $3.99 after 20 miles the engine started running fine even cleared the P0300 code automatically

To whom it may concern: I have a 2004 Nissan quest 3.5 L engine and recently the timing chain was changed when I got the car back I was getting a code P0305, I installed new spark plugs you coils and new injectors, and I also check compression which was excellent any ideas as to why I'm getting this code? Is it possible that the timing chain can be off one tooth?

Looks like a neat tool for the price. Might add one to the trucks box as a travelling tool.

I have a 2003 Suburban with a P0300 code. The rig runs great down the road, but has a rough idle, with the CEL coming on at idle as well. I watch your video and bought one of the Topdon scanners. I've been leaning toward this problem being a vacuum leak issue, as the short term and long term fuel trims totaled over +10% on both banks. I have found a split vacuum elbow on the manifold end of the fuel pressure regulator vacuum line and another bad line at the PVC valve. The fuel short term fuel trim is running near zero now and the long trim is dropping slowly the more I drive it. However, I'm still getting the 300 code after it idles for a while, so it looks like I have more problems than vacuum leaks. I noticed the the spark advance is bouncing quickly between 10 and 25 deg, on the data stream, at idle. The misfire data does not come up on this rig, so I don't know which cylinders are misfiring like you did in this video. I did notice that the ignition timing in the data steam on the truck in the vid is pretty steady. I don't know if my PCM is changing the timing to compensate for the misfiring, or the timing changes may be causing the misfire. It still runs a little rough at idle, but not like it has a dead cylinder or anything, just a slight vibration every 5 seconds or so. Have you ever seen this problem? I was thinking the crank sensor might be going, but I hate changing parts without more evidence that's the problem. UPDATE: The compression in #3 cylinder is 120 psi, which is about 25% lower than the highest CRAP!!. Others run around 155.

P.O. 300 code is a parts replacement bonanza, I had that code on a 2003 6.0 Silverado, it ended up being the solenoid was shorting out to block which melted the crankshaft position sensor in block . It took me a while to figure that one out, I was afraid to take it anywhere because it could be so many things. Stayed awake at night trying to figure that one out, being a shade tree mechanic.

I replaced all my spark plugs and ignition coils that's what helped me fix mine.

Great video Tim. Nice to see an honest hard working shop owner that knows his stuff.

Excellent video that is a nice scanner. I like that you can see see fuel trim what year does it go up to?

Great video, thank you for sharing this!!!!!

My friend you are a great mechanic! I wish you lived in Connecticut cuz I need help with my 04 Jeep Liberty that has a po300 code.

Hello sir,I replaced lower and upper intake gaskets and I first got a p0306 that went away and now I got a p0300,would u happen to know why!!

Thanks Sob dealer

You know what, im really not supprised that the dealership tryed to rip off that customer with fake bullshit :-(. It doesnt build trust in dealerships. :-( Hopefully he has learnt a lesson and has you do a regular scheduled maintainance checkover. Worth every penny :-D The topdon looks very handy for the diy man, much better than the very basic code readers. Not pro, but not paying pro money, a step up for the diy man :-).

You said it. Don't get carried away with one or more trouble codes. Stick with the basics otherwise you may end up chasing your tail. I'd rather have your bill instead of the one from the Chevrolet dealer.

I've got my 2006 SS trailblazer throwing a po300 code I changed plugs and put those NJ k then they're in new plug wires and I'm still getting the multiple misfire that throwed a purge bath cool one time but then it didn't throw it again and I cleared the codes out and put a new throttle body and I'm still having a misfire multiple misfire

The USB is to update it. A Actron CP9680 has code-connect to diagnose codes. EBAY has it.

On board monitoring test did not show misfire data on my nisssn frontier 07. Why is not getting it?

I have a 2004 Chevrolet Express Cutaway 3500 van with the 6L engine and 106,000 miles. I have those codes showing. I sure hope my fix is that easy.

Just curious as to why the main issue of the oily plug was not addressed; most likely being a leaky valve stem seal in this case. Though the vehicle is running fine for the time being it's simply a temporary fix or band-aid. Also I'm curious as to why the Freeze Frame Data was overlooked. Other than that it was a good partial diagnosis and a great demonstrational video!! Thanks for the upload!! Just goes to show that you simply cannot trust even the dealerships ( as I've warned many of my customers over the years ). It always pays to see or at least get a second opinion from a solid, reputable Technician.

Hey I need help. I recently had a used 5.3 put into my 05 Silverado. But now the CEL flashes. I had a bank one censor one code so I changed it... And the code stayed away. I changed all the plugs, coils, and coil wires. The CEL still flashes after driving 10 minutes. And comes on every 5 after that. I checked for vaccume leaks. And didn't find anything. What else should I do?? I still have the p0300 code

Same thing happened to my sister-in-law. Had 5 codes stored and dealer gave her a $1700 invoice. I had her order tune-up parts and I replaced them for about $300 cost. Van purred so good she called me to ask if I put a new engine in...😆

I had the same issue with mine only I had a Misfire on 7 changed the spark plugs did a tune up maintenance this time it’s worse. It gave me the P0300 code saying multiple misfires any suggestions? I’m not a mechanic whatsoever just basic information from online.

i’m sure it was said already, but the word: “Stealership” is fitting

Great Video. I have #5 Misfire on a 4.3 L six cylinder. I will try the spark plugs first. Then I thought about replacing the #5 injector. Opinion?

I have a 2011 Jeep wrangler w/3.8l and I'm getting a PO300 CODE. I've changed the plugs, wires and pcv valve and it runs great while sitting still, but as soon as I put the transmission in drive or reverse it starts sputtering and shaking badly. When I put transmission back in park the sputtering and shaking stops, but there's a popping noise that comes from the shift lever area which sounds like a loud puff of air. I was wondering what could be causing the problem?

The biggest cause of a P0300 is the battery. Every inspection should start with testing the battery, then go from there. To set a P0300 code it has to be something the computer directly controls, like the coils and injectors. It will not set a P0300 from carbon build up, sludge, worn or bent valves, worn rings or a hole in your piston.