P0306 code on an 01 grand prix gtp what would cause this. I have already replaced plugs and coil packs to no avail. Any ideas?
Have you replaced the spark plug wires? If not, replace them. Plugs and wires should be replaced together. If that doesn't solve the problem check for a bad fuel injector on cylinder #6 (P0306 is a misfire on cylinder #6). If that's ok compression test that cylinder. HTH. -Jim
Plug wires just replaced and new injector on #6 and has good compression
Wait until after dark (no joke) and start the engine. Open the hood and look for sparking at the #6 plug wire. If you see any, the plug wire is either defective or not fully seated on the spark plug. This will cause a misfire. If you can't see any sparking get a spray bottle of plain water and mist (don't saturate) all around the engine, while it's running. Be sure to mist the plug wires and coil pack areas. Again look for the sparking at #6. HTH. -Jim
Did that and no sparking
Check to see that you have spark at that individual cylinder. Also, using a noid light, see if you have a trigger signal to the injector. HTH. -Jim
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