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
  • MEMBER
  • 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
  • ✓ASE Certified Mechanic
  • 110,194 POSTS
  • ASE Certified Mechanic
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
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