Thread: po302 misfire after bad overheat...

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  1. #1 po302 misfire after bad overheat... 
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    Hello all I'm back again with a new/old problem. I have a 2003 3.1l with 173,000 miles.The other day my water pump went out on me on the freeway and the car shut off. I limped it home. Drove it to the auto store the next day, it was overheating, andback home. Replaced the water pump,and a couple hours later went to fill it with water. At this point I accidentally sprayed the coils and top of the engine pretty good with the hose.

    After filling and bleeding the system I noticed a check engine light came on and began blinking. I pulled the code and it was a po302.

    I checked for spark at the coil pack which it had and then I pulled the plug. The plug was fouled up pretty thickly and it had wet fuel on it that soon evaporated. I replaced the plug with a new one and the car ran good for about a block, no misfire at all according to my creader crp123 but then started flashing the service engine light, and registering misfires on 2 again.

    Any clues aside from you shouldn't run water in the cooling system? Oh and I've bypassed the heater core and removed the thermostat btw.

    Thanks!
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  2. #2 Re: po302 misfire after bad overheat... 
    Turbo is the way to go. Fivefingerdeathpunch's Avatar
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    Try some electrical grease on the coil packs and plug.

    Maybe even mist the wires late at night with water and watch for a spark jump, that will a show a misfire related to a faulty coil or wire arching.

    Or you overheated it so bad that it blew the head gasket and now has low compression in that cylinder.

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  3. #3 Re: po302 misfire after bad overheat... 
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    Nope I blew a head gasket. I was blowing white smoke. 30 minutes with blue devil stopped the smoke. 50 minutes and the misfire disappeared. I've gone about 377 miles since I posted/ poured the blue devil and neither smoke nor misfire has apppeared
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