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urgent need help misfire

gtcoup

gtcoup

New member
99 gtp. 175k. underload like getting on the highway im getting a light misfire from cylinder 6. wires are fairely new same with plugs. pulled #6 and swapped it havent gotten to drive it yet, but it looked good. but when it first misfired my girl was behind me and she said it smelled like a firework? but didnt notice if it was smoking it was dark out. im confused anyone got an idea? i just bought this car and this happened on the ride home. i relle hope i didnt just blow my money on a junk car. i really need hhelp guys im trieng to get this car on the road. thanks in advance :th_winking:
 


one thing to check to is the other wire that comes off #6's coil pack. #3. make sure it is good too. they fire in a loop. two at a time.
 
Ok just wanna point out that you say the wires and plugs are fairly new then you say you just bought the car.... So are you TRUSTING the people who just sold you a car that is misfiring? I would start with changing those.. I always change plugs and wires when i buy a car. If nothing else then take the spark plug out of the missing cyl. and look at it. Make sure it is not covered in oil or coolant.
 
If you're positive it's #6 missing, swap that coil with one of the other two and see if cyl # 6 still misses or is it the cylinder that is now using the #6 coil tower. Follow me?
 
I pulled plug 6 and 3, both look good. And the wires look good but I'm gonna swap them off my gt and see what happens I guess
 


swapped coil 3/6 to my gt. no missfire. checked resitance with ohm meter and theyre the same. i pul some seafoam in the tank but im holding off registering it till i figure this out. and im gettin sketched out ridin around ataching plates. ideas people?
 
ses flashs then steady. ive had missfire beofre in my gt and it was alot rougher. its not a bad missfire (mo missfire is good just saying) ive driving cars that have had somme bad missfires and this isnt rough at all. im stumped. coil, plugs n wires are goood. wtf i jsut bought this car starting to thinki got burned
 


it could be your fuel injector, ive never had to do a fuel injector on a 3800 before but that could be the problem change it out and see if it solves the problem other then that i cant think of what it would be
 
i agree with asite57 if your miss fire does not follow the coil pack it is possibly the injector for some reason when they miss no one ever checks that.
 


Ensure the wire isn't touching the O2 sensor or wiring. On a W body..there's not a lot of room back there and it can happen.

Look at the plug..any damage etc? Is it carboned up or does it appear super clean?
 
OK so I had the same exact problem with my 99. This is y I asked if you had another code like a lean bank 1 or something. Car misfired on #6. Changed plugs wires and injectors. Still no change. Sprayed brake clean around vac lines. Found underneath snout the supercharger gasket was bad. Not saying its your problem but worth a cshot when you have no other clues. Make sure to get all the way around and be thorough. I never caught it the first 2 passes.
 
no other codes, just misfire #6/ p0306... pulled that plug and a couple others, they all look the same. clean no carbon built up on them. wires are out of the way no contact with o2 wire....
 
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