Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hello, my name is Bobby. Thank you for the question. Can you tell me if the check engine light is coming on? Does the engine run rough? If so when does it run like this?
Have you scanned the computer for codes?
Thank you. I wanted to make sure that there was nothing besides the 300 code. From what you are telling me it sounds like you have a lean condition. Most of the time on this engine this is caused by either a vacuum leak in the intake manifold, or more commonly it is a restricted fuel injection spider unit. This is the most common failure on this engine. Some shops can clean it, but most of the time it needs to be replaced. I typically prefer to pull the upper intake manifold and see how the plastic nozzles look on the engine of the injectors. Most of the time they get clogged with carbon and this occurs.
Did you happen to check vacuum with a vacuum gauge also?
Thanks. I would like to see if you can get a manual vacuum gauge and see what it reads at idle and while holding 2500 rpm. I want to know how steady it is also. Does the misfire smooth out at higher rpm or get worse?
The thing that gets me is that it is affecting one side of the engine only. The only other thing it would possibly be is the O2 sensor or possibly a computer issue, but that is not too common on this vehicle. Have you replaced the O2 sensor?
Thank you. Either you have a computer failure or you have a wiring issue. It is common for that injector harness to fail and cause this if it is keeping the injectors open for too long. Does the truck run any differently if you move the harness around while it is idling?
Your vacuum should be higher than that at 2500 rpm. It should be above 20 HG. You either have a timing issue like a bad distributor, a restriction in the exhaust, or a stretched timing chain.
Keep me posted and we can continue from there is needed.
Hi, My Name is***** have over 20 years experience repairing vehicles. I am a ASE Certified Master Auto Technician. I am confident we can resolve your problem together.Please remember I don't know your skill level. I can't see, smell, hear, or touch the vehicle. It may take a few back and forth replies to get to a satisfactory resolution.I also try to give all of the information you may need expecting a positive rating. If there is any reason I cannot get a positive rating please let me know.
I am not real sure why he opted out. Are these long term and short term fuel trims + ? Have you checked for a vacuum leak. These are kind of common for a plenum leak
I have not opted out of the question, but would be more than happy to opt out if you would like Samuel to help you instead. Please let me know.
I agree with BobbySS that the fuel injector spider is suspect. You definitely have a lean condition caused either by vacuum leak or plugged fuel injector spider, Both are very common on this vehicle
What is the bank 2 sensor 2 reading?
Oxygen sensor reading