Experienced a misfire and found by way of Osiris/Cypher that I had multiple cylinder misfires. I checked several things based on causes for the codes and fixed a possible leak (cracked gromet) under the air intake tube. Car ran perfect. The following day I drove it to work and no problems, but upon returning in the evening, the misfires came on again. I connected Cypher again a got a P0302, misfire for number two cylinder. I checked the coil again and noticed a bulge on the side of the coil. Went to the dealer and was told that the bulge indicates the coil is going bad and to check the grounding all around the car (battery to fender, on the driver side wire harness w/ ground to fender and the ground to the alternator. I was also told to check the MAF and spay it w/ injector fluid for cleaning.

Any suggestions by anyone???

 

Is anything done to the car? Any electronics/ECU,WOT shift modules, tacho????

Needm more information, coils usually dont go bad for no reason..

 

Yes. I've done a few things to include Osiris/Cypher.

 

So call up their tech support and see whats up, and why your getting the P300 which is usually due to a lean idle condition. Did it start AFTER the reflash? Your pretty evasive about your set up and most likely will not find the answer your looking for here.

 

I think I found the answer. It turned out to be one bad coil which I replaced. I cleaned the grounding terminals as I was told by the dealer and got a couple of battery cables which I used to ground the block to the chassis in different places. Right now is working fine and there are no codes present. I'm not being evasive about the set up which in the question I asked didn't have much to do with it. I have the basic boltons everyone has, mainly intake and exhaust. "I guess that I should have rephrased my question as "What causes code P0300 ?" Thanks for your help