This is copy pasta from the thread i started at GP forums

First off I've searched this forum for the past 2 days to try and find a solution and I still can't figure this out.

My roommate has a 97 GTP with 215k, the only mods being an HAI and ported blower. A few days ago on his way home from work his SES came on and he said the car started sputtering and surging. He took it to get scanned and was told it was a multiple cylinder misfire. So we replaced his plugs and wires and everything seem fined at idle, but the moment the car started to receive boost the misfire came back. We checked all the vacuum lines and found out the line for the bypass valve broke, fixed that yet the problem persists. I swapped all 3 of his coil packs for the ones in my 03 Monte Carlo SS (l36) and still nothing. After all this we decided to unplug his battery and on his way home from work today hes going to have it re scanned to see if there's anything new.

All the other threads I've found about the subject have either fixed it with what ive already tried or have died.

We've tried swapping out his MAF for a new one straight out of the box, and it's still being silly. The only bit of information I found on here thats helping is someone said that running the car with "no exhaust" could cause a burnt valve. Awhile back we had to replace his driver side engine mount and in the process broke one of the bolts on the crossover pipe causing a pretty bad leak. The car has a "rebuilt" engine and tranny so I'm assuming the LIM gasket has been replaced.

That's all the information I can remember at the moment, I'm sure later today I'll be able to give some more. If theres any more info that might help just let me know.

 

Fueling problems can be the source of a misfire.

Something like a stuck open injector, clogged fuel filter, etc.

 

I was thinking a clogged a or broken injector, maybe a messed up connection but that doesnt explain why its fine until it gets boost, and after that is constantly off. I know the injectors go into different spots on the l67 and l36 but are the stock injectors the same? Would I be able to take them out of my monte carlo and slap em in the gtp as a test?

 

the GTP has a higher flow rate.

I know when I turbo I have to swap mine to the GTP as a minimum.

 

Any way to flush or revive injectors?

 

Which code do you have? Random misfire, or on a specific cylinder?

I think you could always move the injector as a test if it is specific.

 

I wasnt with him when it got scanned, he said it was a multiple cylinder misfire, I dont know if it said which ones.

 

typically not, probably a p300 and not a p300# then.

I would think it's not just ONE cylinder and maybe a failing fuel pump or a clogging fuel filter?

Then when the car is in boost and commanding more fuel it can't get it?

 

Could autozone check the pump or would I have to swap it for mine?

 

Idk if they can do fuel pressure tests or not