Thread: 04 gtp misfiring at 3/4 to full throttle

hey guys just picked up an 04 gtp had many of the 98-2003's but cant seem to track down my misfiring issue on this 04.

things ive done.
1. changed to steel lim gaskets.
2. new plugs and wires.
3. checked vacuum lines.
4.cleaned tb.
5. new fuel filter.
6. new air filter.
7. drilled holes before cat to see if it was plugged no difference.

i have no cel, however a couple days ago i got limp mode with code p1516 but has not been back since. dont dare throw a 100 accel pedal at it til i could be certain thats whats causing it to spudder terrible under 3/4 to wot you can run slight boost pulls good. till you hit that 3/4 mark then just sputters out. car is completly stock even stock airbox. anyone have any more ideas? idles great. 91 oct only been in it.

i see the 6/3 coil has been swapped and the 1/4 2/5 are the original. i should have specified it does have 253k on it....

Can you live Scan it to see what cylinder is missing?

unfortunately, i dont have a way to live scan. what im figuring is it sounds like i got 2 cylinders cut out, one is pretty distinctive vs 2 cylinders. being it has that many miles it could be a number of things.

Originally Posted by rileychris

unfortunately, i dont have a way to live scan. what im figuring is it sounds like i got 2 cylinders cut out, one is pretty distinctive vs 2 cylinders. being it has that many miles it could be a number of things.

i did ohm out the injectors they all come back at 13.0 to 13.2 ohms forgot to add that up top in the original post.

ok so i got the studdering figured out, it was in fact the ICM so if anyones getting the same issues, hope this post will help you out. thanks for the help guys

Bad tac or bad communication wire between the tac and pcm... Do you have any U codes? If not then prolly as bad tps but you have to replace the tac because the tps can't changed seperate