Thread: 05 Misfiring

I have an 05 grand prix gtp and it has had a slight misfire at idle for alittle while, but yesterday morning it started getting progressively worse and now is a constant misfire. It has brand new factory replacement plugs and new front o2 sensor. I replaced the intake gaskets 100 miles ago and also has speed daddy headers with no cat. I swapped over a ignition control module and coils from a good running car and the problem persists.

Any ideas what it could be? Also has 165,000 miles. I'll have the codes checked tomorrow morning.
Could it be anything related with it not having a cat?

Thanks

i had the codes read and pulled up mostly o2 sensor codes and a maf code. so i swaped the maf off my dads 05 grandprix, it seemed to help alot but there is still some mising at idle. and if you let off the brake you can feel it jerking until you give it gas it seems to go away. is this something normal to a supercharged car ? should i have it tuned just for the headers? i cant seem to find a o2sim for an 05.

thanks

sounds like you need new plugs and wires, the o2 code is probably being set due to the no cat factor. as per your sig.

and junk yard mafs run about 40 or less. less, if you can pocket it. ( so dad gets his back)


and you say mostly. were there other codes? like for a misfire?

sorry, for the late reply. i have new factory replacment plugs and wires. the only codes the tech 2 ( i think thats witch one it is) scanner could pull up were several O2 ad the maf. One O2 code was for bank 1 sensor 1 for slow response, turns out its a bosch so i ordered a new acdelco to replace it.

i stumbled across a thread talking about removing the rear O2 sensor on 01+ cars. Well when i put my headers on i pulled it thinking i wont need it now (dont know why i thought that). The thread was alittle confusing, so basically my car is stuck in cat diagnostic mode? The car seems to be running rich, so should i buy a back sensor and a front sensor and throw them in and maybe it fix my problem, even with no cat?

Also im going to clean my egr since the scanner showed it was moving slow, or maybe just delete it. And fix a small crossover exhaust leak.
I did get dad another maf. lol

thanks