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P0300 code please help!!!

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Old Feb 16, 2011 | 08:07 AM
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Default P0300 code please help!!!

Ok here is my problem. I have a bolt-on M6 02 Z28 with 102k miles on it. I have just recently changed my plugs TR55s, wires MSD 8.5, maf 85mm SLP, alternator 145amp truck type, and battery red top optima. I had a light flickering and missfire problem for a good while. Now that i have all these new parts on the car it runs a whole lot better. Better than it has in a long time!! My lights no longer flicker and no more unburnt fuel smell, but i'm still getting a missfire code and O2 codes due to my long tubes. The car is not missing at idle and the only time the missfire code comes up is if i'm cruising down the road. My SES light flashes like there is a party going on in my car for about 45sec to a min! I am wondering if a vibration from having a polly trans mount on my car could be causing my missfire codes? Anyone else had this problem? I'm drawing a blank on what it could be now! Any help or suggestions are very much appreciated!!

Thanks!!
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Old Feb 16, 2011 | 09:20 AM
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Anyone?
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Old Feb 16, 2011 | 09:38 AM
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get a tune!!! your ses light is flashing cause you have not tuned out the rear 02 sensors. and the missfire can be caused by the long tubes as well. at least get a mail order tune from frost
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Old Feb 16, 2011 | 09:46 AM
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I have a custom tune in the car already.
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Old Feb 16, 2011 | 09:49 AM
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Checked plugs and wires?
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Old Feb 16, 2011 | 09:57 AM
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Yep, all where tight. This this problem is driving me nuts!
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Old Feb 16, 2011 | 07:46 PM
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Anyone else has had this problem, and fixed it?
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Old Feb 17, 2011 | 12:38 AM
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You need to determine which cylinders are misfiring. Only way to do this is with a decent scan tool otherwise you will be shooting in the dark.

You can then determine if its a single cylinder thats misfiring, or an entire bank which will drastically help your diagnostics and prevent a lot of parts hung that arent needed. A front O2 sensor can definately cause an entire bank to misfire regardless of the longtubes.
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