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?


Asked by Apr 25, 2015 at 06:46 PM about the 2001 Pontiac Grand Prix GTP

Question type: Maintenance & Repair

5 Answers


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

Best Answer Mark helpful

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

Your Answer

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