Code P0301

[scannr89]

did any plugs look cleaner than the others ?

[Gridgirl]

Originally Posted by scannr89

no..I was thinkin intake gasket

I have no idea. I wouldn't have guessed an intake manifold leak could introduce antifreeze. You mean the gasket between the plenum and the tops of the valves? Seems if that's it, it shouldn't be tooo tough to replace....

[Gridgirl]

Originally Posted by scannr89

did any plugs look cleaner than the others ?

Don't know yet- I'll pull the plugs tomorrow morning.

[scannr89]

I can't remember their being coolant near centre ports( I think you said # 4) that would be a centre cyl. checking colour of plugs is a good idea. if it is a coil you should have a miss on both cylinders attached to that coil.

[Gridgirl]

Originally Posted by scannr89

I can't remember their being coolant near centre ports( I think you said # 4) that would be a centre cyl. checking colour of plugs is a good idea. if it is a coil you should have a miss on both cylinders attached to that coil.

So if the coil was at fault, cyl 1 would definately be misfiring too? The scan tool at the auto parts store only showed P0304.

[scannr89]

I would like to see misfires in the data stream of scanner, they hold a history of misfires along with real time. it makes it alot easier to pin point than just relying on codes

[GTP Dad]

If you have a misfire the first thing I would do is change the plugs and wires. These are the two most common causes of misfires on cars. Since it indicates Cyl. #4 then pull the plug and check it. I doubt you have an intake problem at the present time especially if you are not seeing any coolant loss, chocolate colored oil or a plume of white smoke out the exhaust.

One other thing to try if the plug and wire does not correct the issue is to move the #4 injector to another cylinder and see if the misfire moves. If the misfire goes to that particular cylinder then the injector is bad.

As for the Bosch plugs they usually don't work well in Pontiacs. I have a GTP and left them in for about 5K miles before changing them to autolites. I had a misfire and once I replaced the plug it went away.

[Gridgirl]

Replaced the wires and plugs today (only took an afternoon- last time took three days!). The wires I replaced in Sept were still under warranty- so a brand new set of free wires from Advance Auto. Then new plugs are the OEM AC's. The three month old Bosch's all looked fine. Took it out this evening, got it up to operating temp, and no sign of misfire. So far, so good! Tomorrow, back to Advance to use ther scanner to clear the misfire code, and hopefully reset the check engine light.

Thanks for the help, it is much appreciated! AF is terrific.