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misfiring but no code

firefighter6180

firefighter6180

New member
ok the title doesn't do this justice,
couple days ago i had a misfire, the ses blinked at me when car was going up hill but never did it again, found a p0303 and changed the wire and spark plug on cylinder 3, now it still misfires under load but no light or when i start it, it will have a rough idle and sputter constantly but it is either one or the other and not all the time. So im stumped, i was considering fuel pump, fuel pressure regulator or fuel injector since im not getting a code anymore? i have not tested the coil yet
 


could be a clogged cat. how many miles you have and year?

try swapping injectors around, and the coils around, if the misfire moves the last one you changed is the problem.

or a bad icm, the part under the coils, it could be bad.
 
How old are the rest of the plugs and wires? If old I would start there first. Do you know anyone with a decent scan tool that will show individual cylinder misfires? This would be the easiest way to see which ones are causing the problems.
 
i will try moving parts around first and go from there, its 2002 gt with 211,00, headers, magnaflow exhaust system rear 02 delete, and k+n air intake
 
i dont think it will clear up a misfire, if thats whats going on.

no o2 in the back, so you got a hi flow or no cat installed?
 


If the cyl misfire code is not reseting it will not do any good swapping parts around because you will not know is the problem has moved. Do you not have access to a scanner as asked before?
 
If you go into live data does it show you cyl 1 misfire, cyl 2 misfire etc in the data. If so you can look to see where your misfire is coming from. If your scanner does not show those it may be worth finding someone with one that does. The pcm must see a certain number of misfires within a certain amount of time to set a p0301 or p0302 etc. That is why it is not setting a code or the check engine light right now, it is not seeing enough even though you can feel an obvious misfire.
 
Alright man i looked up specs on your scan tool and it does not look like it shows live data. Sorry so this wont really help you out much. I cant be of much help without knowing what cyl is currently misfiring.
 


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