Chevy Silverado GMC Sierra P0300 Diagnosis and Repair

Today a customer dropped off his 2005 Chevy Silverado 5.3L pickup complaining of a rough running condition, black smoke coming from the tailpipe and a check engine light on. Watch this video for the twists and turns in this interesting case study and build you confidence to diagnose this common issue effecting many Chevy and GMC trucks and SUV's.

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[LaramieJim]

You are not a fat, old, balding guy who is losing his mind. You are an experienced, distinguished, full sized car repair artist. Always enjoy your videos

[MamaTata]

5 years later and your video is still helping people 😂. I've been lucky enough to get enjoy the P0300 code on my '06 GMC Sierra 1500...
I felt that whole "Trying not to cuss, while working on your vehicle (or others).. Especially when dealing with a "bandaid code".. as I have lovingly renamed them
.. 😂 Thank you for this! Getting the diagnostic machine back out for another round on the O2 sensors...

[gabrielswenson]

'...and you burn yourself just like that...' I finally found this video on the goose chase of fixing my p0300 trouble on an '01 Silverado. This was a very helpful video and a lot of fun to watch. I had no idea a) where the O2 sensors were located and b) that they would effect idle, fuel economy and ride quality. Thanks so much for posting this!

[cameronwickes]

Here’s one for you my 03 Silverado had the po300 code. I changed plugs wires and a bunch of other things and still multiple misfires. After checking the serpentine belt it was a little loose due to the tensioner. After that was replaced it was like a new vehicle!

[josh-ej]

This is exactly the video I was needing, thank you times a million for taking the time to post this. My truck is an 05 with the 5.3 and has exactly this same problem. I thought even tho the bank one sensor one was bad I might be having trouble with the plugs and wires. I had no idea that an oxygen sensor would make a vehicle run rough like that. Thanks again so much!!!

[CatFishMarmite]

I had an 05 z71, had a po300. I didn’t have a scanner so just checked the plugs, the whole passenger side bank were fouled. Dropped the y pipe and the passenger side cat was smoked. I know on those model years the piston rings take a shit and they consume a lot of oil, it always ends up smoking the cats. Knocked out the cats and it ran great. And that was after I took it to a shop and they wanted to replace my cam lol. Needless to say I got my money back from them because they misdiagnosed it. Good video

[maradosmalls]

Wife got her 2001 Chevy Silverado from her dad... whenever it is cold there was a rough idle etc and sometimes would cut off. Changes plugs and wires...fuel pump and filter.. alternator and battery.. so I let her drive my Yukon XL until I got the Chevy straight..scanned it and got the codes...was told to clean the injectors and to change the coil packs.. done...still the same problem so finally ended up getting the O2 sensor...bank 1 sensor 1. They gave me the aftermarket one..had to go back and they had 1 original fit remaining. She seems to be running fine now but I'll know in the morning when time to crank up. Thanks for the video.. really helped me. I pray this is the fix

[mikelokken]

Not sure if it will solve my problem, but this this is the best repair video i have ever watched. Kudos

[xelabound]

I have watched just three of your videos after finding you on YouTube and all three vids fixed the problem I was having. Thank you ever so much for blowing up my parts cannon. You rock Tim!

[gilbertguzman]

Ran a scan and saw that bank 2 was at 0.00 with my truck warmed up thanks for the help easy fix but going to have to get on the ground to do this work wish me luck

[notoriousscottyb]

Great heads up!!!!
A buddy and myself pulled an 09 denali 6.0 that had oil leaks everywhere. When we installed it and finished it off it was running terrible (on odd bank) and we werent sure why... P0304. We went after # 4 no coil operation. Checked fuses power supply etc.
Found it was the whole bank out. I figured I would google it ( yeah right! Who else has had this problem...nobody)
Your video popped right up.
It saved me hours of diag time. Went right to it found a broken wire, fixed it, cleaned and tightened the ground....Done!
Thank You for putting this out.
When you dont have a scanner or wire schematics life can suck.
You helped me avoid the suck.

[martytruelove]

I would use your shop if it wasn't such a drive...do appreciate your advice.Knowledge through experience is unbeatable.

[NoeG]

40 seconds in, I clicked like and I subscribed. Sometimes you can just tell when someone knows what they're talking about just by how they talk about simple things

[Heather-xmul]

This was very educational and super helpful. I love that you tried to get the most helpful angle for the various steps! And seeing that other cat was helpful too.

[Unwantedbaby]

Best video I’ve watched. Honest man that truly wants to help. Subscribed!

[sammec]

Reminds me of my dad they way you work and explain and talk, and thanks for the video, I never knew o2 sensor shows misfire code. 🙏

[brandonjohnson]

Your O2 sensors control your air/fuel ratio. If you have bad sensors your vehicle will create a "lean" condition which makes your vehicle add more fuel resulting in poor/rough idle and drastically lower your fuel economy. Not to mention you can burn out a valve or destroy your catalytic converters because they are catching all that unburnt fuel from the vehicle increasing fuel to balance what it thinks is a "lean" condition. Clean O2 sensors, Mass Air Flow Sensor, Idle Air Control Valve, and Manifold Air Pressure Sensor (if it's equipped) are a absolute must to keep that engine healthy and happy.

[jaysonarocha]

Just like you I had a P0300 so I dug into my 2010 Suburban 5.3L and found out the owner before me had installed wrong parts on the truck. They had ACdelco 6 spark plugs incorrectly gapped and copper when it should have been iridium plugs. I put the spec ones in with new wires and now no misfire.

[slofouru]

Great job. Thanks for being considerate enough to share your time making the video to help everyone. 👍 I'll definitely check that data when I'm checking my 03. Those sensors aren't super expensive but sure can cause headaches. Mine has the same dtc at 77k miles

[ever]

Good morning! thank you for this video it really helped me out my truck was doing the same thing it's running smoothly now, have a bless an awesome day