Thread: Random CEL light

2000 Grand Prix GTP 184xxx miles

Guys I need some help here!
When the car is just idling, whether Im sitting in the driveway or at a light there is no CEL, when i accelerate or push on the gas pedal after about 30 seconds the CL starts flashing. When i go back to idle after a minute or two the light goes off. Checked it with the scanner and it shows misfire in cylinder 3. Car doesn't run rough so i don't think it really is misfiring. My scanner wont do live data so I can't look at that but i have pulled the wire and the plug and it is firing like it supposed to. I have swapped and replaced plugs, wires, coil and injector and it is still doing the same thing. Thought it might be a manifold gasket but it doesnt make sense that it would go away at idle.

Any ideas?

Well I've done plugs and wires and replaced that coil and that injector on #3 so I guess I'll check the cat. Thanks

Here's some additional reading on your issue--> Cylinder 3 misfire Tried everything I can think of

Also, what did the electrode look like on the plug that you originally pulled out of #3? Gap still open? I also assume you run at least 91 octane fuel that the S/C cars require.

Plugs all pretty much looked the same when I did the TU. 91 or 93