2003 Chevy Silverado Check engine light

GBOB37

MEMBER
2003 CHEVROLET SILVERADO
V8
4WD
AUTOMATIC
90,800 MILES

The truck starts fine but when I try to punch it down in the city or try and take it on the highway the truck is really sluggish and the engine light comes on. I had it analyzed and it said check Mass Air Flow sensor as well as irregular cylinder fire. I started by replacing the spark plugs and wires then I replaced the fuel filter and finally the MAF sensor. What next? Could it be the fuel pressure regulator? Thanks, Gary

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

Hi gbob37, Welcome to 2carpros

Check the fuel pressure to rule out the fuel pressure regulator and fuel pump. The pressure should be 55-62psi. Misfiring can be caused by worn or fouled spark plugs, a weak spark (weak coil, bad spark plug wire), loss of compression, vacuum leaks, anything that causes an unusually lean fuel mixture (lean misfire), an EGR valve that is stuck open, dirty fuel injectors, low fuel pressure, or even bad fuel.

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Wednesday, April 14th, 2021 AT 6:49 PM

GBOB37

MEMBER
2 POSTS

Raz, Thanks for the response. Took the truck to our local Muffler Man for a complete readout and it turned out that one catalytic converter was plugged. $200.00 to replace the bad one or $600.00 for complete direct fit. Should have checked on line first. Found an Eastern direct fit for $325.00 including shipping from Discount Catalytic Converters. After replacing the fuel filter, plugs and wires then the MAF sensor I got fed up and told them to put the direct fit unit on. Runs amazing now! Tell others about my journey and also tell them about Discount Catalytic Converters. Thanks Again for Your Help, Gary

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Wednesday, April 14th, 2021 AT 6:49 PM

SQM

MECHANIC
6,383 POSTS

Thank you very much for sharing the information on the fix.
I have attached the catalytic converters replacement procedure below, for anyone who might be looking to replace them.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms
https://www.2carpros.com/articles/catalytic-converter-replacement

Please let me know of any questions.
Thank you.

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