Check Engine Light

2003 CHEVROLET TRAILBLAZER
92,000 MILES • 6 CYL • 2WD • AUTOMATIC
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CHEVYTRUCK03
  • MEMBER
  • 8 POSTS
Check engine light on. Code P0300. Replaced spark plugs, replaced air filter, replaced fuel filter. The coils were checked by disconnecting the electrical connection of each one and # 4 and #3 coil had no change in idle. Now code P1515 comes on. What does it mean if no change in idle and why the P1515 code? Runs rough and accelerates slow and gets very poor gas mileage. Please help
Apr 19, 2011 at 1:20 AM
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KHLOW2008
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  • 41,814 POSTS
No change in ilde means the 3 cylinders concerned are not firing. Try swapping the coils with other cylinders and if the conditions migrates, the coils are bad.

The disconnecting of the ignition coils can trigger the fault.

DTC P1515: PREDICTED VS ACTUAL THROTTLE POSITION CORRELATION ERROR

Have the misfiring resolves and retest if the problem goes away.
Apr 19, 2011 at 9:15 PM
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