GTP stalling issues
 

My gf's 2001 gtp is having intermittent stalling issues. It will randomly stall and lose spark. Sometimes it will restart and run rough and other times it wont start at all. Ive replaced the maf, crank sensor, tps all due to codes, and even the pcm. I replaced the icm too then returned it cause the problem still was there. Im not sure what else to try. Figured id ask on here cause i got negative answers on grandprixforums.net

Whose coil packs are on there?

Stock gm packs

Any codes now? It only loses spark?

No the CEL isn't on now, but it loses spark and from what my friend said the injector pulse too, since the test light did not light up.

Did you use a test light or a noid light to test the injectors?

check the fuel pressure sounds like a cloged fuel filter or bad pump i had the same problem on the 88 gta

I've had issues with the underhood fuse blocks on them. they would run fine then just cut out and half of the fuse block would lose power. I want to say it was a faulty fuse block but I can't remember, may have been an ignition switch too. I think I have a test switch if you want to try it. Ignition switches were fairly common for other issues on them, mostly headlamps, radio and hvac turning on and off.

Does it restart immediately after it stalls? The ICM and MAF usually won't restart until they cool down for a while. I've also had a few issues with cam sensors. A cam sensor usually won't cause a stall tho.

Edit: I also had a Buick with a 3.8 that had loose terminals at the ICM connector, would run perfect for a while then just stall. Would occasionally restart. I could make it stall by manipulating the ICM connector while it was running. I have the terminals and the tools to repin the connector if it turns into this.

when you say..." sometimes wont start at all" do you mean it cranks over but doesn't fire or that it does nothing when you turn the key? I ve seen them shut off & no crank, then work fine from corroded battery terminals. could have bad module that the coils sit on too.

Yeah I was starting to think the module could be bad as well but he said he did an icm.

Im not sure what exactly its called but it plugs into the injector plug.

Fuel pressure is perfect.

Sometimes it immediatly starts and sometimes not. I played with the icm and pcm harness and nothing. Still won't start and when its running if I play with the harness it does not stall.

It always cranks, just wont fire sometimes. When it does start back up immediatly I have to hold the gas down to keep it running it will dump black smoke and sound like it has a huge cam, then it will clear itself out and run perfect..until it stalls again.

I know it's a 2001 model year, but since it buts up to the end of the documentation...

Does it have a fuel pressure resistor?? If so, get rid of that regardless of if it's the problem.

The coil packs bolt down to the icm. There are two pins that rise up per pack and penetrate it from the underside. When its not starting, take a test light and key on check for power on one pin. Then check while cranking that the other pin pulses ground.