Codes P0300 or P0303, Traction control off, service Stabil Trak, and check engine light turns on

2007 CHEVROLET AVALANCHE
201,000 MILES • 5.3L • V8 • 4WD • AUTOMATIC
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KINSEYJAMES
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  • 25 POSTS
OBD2 scanner gets codes P0306 twice or P0300 or P0303. I have checked spark plugs, coils, wires, cleaned throttle body, changed out air filter, cleaned mass air flow sensor, wheel speed sensors are okay. The fuel pump is working fine, I can hear it. It's not running lean or no lean code. I notice the misfire in the idle, no reduced power light. I don't know what else it could be. help
Jun 17, 2022 at 4:52 PM
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JACOBANDNICKOLAS
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  • 110,175 POSTS
Hi,

If the plugs have spark and fuel pressure is within the manufacturer's specifications, that leaves compression, injector issues, or timing.

Other than at idle, do you notice a misfire when the engine is under a load? Also, are you sure there are no engine vacuum leaks? I realize there are no lean mixture codes, but it's still possible.

Is there any smoke from the exhaust? If so, is it dark gray/black, white, or blue? Any strange odors from the exhaust?

Let me know.

Joe
Jun 17, 2022 at 9:14 PM