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Jerry Newton
Jerry Newton, Chevy Technician
Category: Chevy
Satisfied Customers: 4413
Experience:  ASE Master Technician, L1, Master GM Technician. Over 20 years of bumper to bumper GM experience.
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Chevrolet Silverado 1500 Classic LT: . My engine light has

Customer Question

Hi. My engine light has been in for some time now. The engine runs fine but when warming up to operating temp, it seems to lag a bit And then all of a sudden it accelerates fine. initially I was just thinking it was a faulty code so I erased it a few times and when at the peek of acceleration the light would come back on. I would start out with o2 codes; p0171, p0101 and p0157. After driving for a few hours I would notice two more codes; p0174 and p2a04. To me it sounds like a fuel pressure problem. what do you think?
Submitted: 1 year ago.
Category: Chevy
Expert:  Jerry Newton replied 1 year ago.
I disagree. Two codes are telling us that you have a lean fuel mixture, and one of the codes is telling us that your MAF sensor calibration is not good. You also have an oxygen sensor code mixed in there, but all of these things combined lead me to believe that it's more likely that you have a faulty MAF sensor, as it will cause all of these codes to occur. You may also have air leaks in the intake duct between the engine and the MAF sensor that will do the same things. I would say your problem is isolated right in that area.
Customer: replied 1 year ago.
OK. That sounds good. Do you have a way that you recommend to text for leaks in that area?
Customer: replied 1 year ago.
Also what else could cause a faulty MAF besides the MAF itself... as I have clearned the original with no luck in change of codes and replaced the MAF itself.
Expert:  Jerry Newton replied 1 year ago.
A leaking air duct would give you all of those codes. There are smoke testers that can be used for this, but for the most part, you can simply take it off and look at it closely, perhaps with a flashlight. Just looking for cracks, or anything that would allow unmetered air into the engine. This is what skews the MAF calibration, the computer has to account for all of the air going in, so if you have unmetered air, you'll not have enough fuel delivery, and hence lean codes, oxygen sensor codes, etc.
Customer: replied 1 year ago.
OK great! Thanks for the info Jerry. I'll try that and see what changes.
Expert:  Jerry Newton replied 1 year ago.
Sure, let me know if you need anything else.