2002 Olds Silhouette Misfire code PO302

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2002 Olds Silhouette Misfire code PO302

Unread post by bowtie » Mon Sep 06, 2010 2:35 pm

I have a PO302 misfire code (misfire cyl #2) problem. The van always starts just fine and then (typically) while it is still cold, the engine bucks on occaision with a misfire (resulting with a blinking SES light) and then once in a while it will set a hard PO302 code. This has been a very erratic problem. I have ran fuel injection cleaner through it which seems to help for a little while, then every once in a while always in the early morning, the misfire will occur again.

I realize that the problem could be with spark plugs, wires, ignition coils, perhaps a dirty or failed fuel injector, a plugged CAT converter, bad ECT sensor, bad MAF sensor or possibly the ECM itself.

Because this problem is so erratic, has anyone else been through this particular problem and if so, what did you discover ? Does anyone have any recommendations for where to begin ? I just do not want to throw parts at this and pray that I hit the right part. Cold weather will soon be here and I would like to resolve this issue before winter.

Thanks for any help you may be able to provide !!! :?


Re: 2002 Olds Silhouette Misfire code PO302

Unread post by MeccBoy » Tue Sep 07, 2010 12:28 pm

The problem your van has CAN be all those parts listed.
If the injector cleaner helps, then i would suspect a bad injector.
Look closely at spark plug and wire, or swap to a different cylinder to see if the misfire follow them.
MAF not very likely, coolant temp sensor- no, Cat converter- no, ECM- unlikely
Stick with the basics.
If spark plug has orange residue, possibly headgasket.

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