Thread: Misfire, running lean

I just bought a 2005 grand prix a month ago, since then i installed speed daddy headers. I have a slight misfire at idle when its in park, it dosent seem to happen while driving or idling in gear. i stopped and got the codes read, it has a few for the converter because its not there anymore. The other codes are P1133 for bank 1 sensor 1, and i replaced that sensor the day after i bought it when it still had the manifolds and converter. P0133 bank 1 sensor 1 slow response. P0243 supercharger wastegate soleniod.

it also has brand new stock replacement plugs and wires, I also ran some fuel system cleaner thew it. I am going to be changing the lim gaskets this weekend and figured i would clean all the grounds and stuff while im in there. I also watched the boost bypass solined and it opens when its running and closed when its off. What do you guys think is wrong ?


thanks
-josh

Misfires at idle are pretty common when modded, most of the time they happen and the PCM doesnt even sense it.

And both those front o2 codes I have gotten right after I did my headers and then went away after a handful of times coming up.

You might wanna get a tune for not having a cat, it does affect MPG's on anything 01+.

I have speed daddy headers and everytime I run 110 I get that code but after a few tanks it clears up just keep clearing it and see what happens

Okay, i was going to wait to tune till i have my other mods to put on and install and tune them all at once. will it hurt anything to drive it with headers and no cat for a few months with out a tune?

I was ust thinking, the check engine light came on the day after i bought it and filled it up with 93 octane. i think the previous owners ran regular would this have anything to do with the bank 1 sensor 1 code on the brand new sensor? Because it threw that code when it still had manifolds and a cat.

thanks
-josh