I need some help please... I bought a 1993 Grand Prix with a 3.1. with a major problem. I got it to drive back and forth to work because I heard they were reliable. I've had it for a few months now and then this started happening. If I'm driving down the road it sputters, the tach jumps around alot and it dies. I thought it was the crank sensor so that's where I started. it didn't fix the problem. So I thought I'd try plugs and wires, that didn't help either. I took my coil packs and ign. mod. in to get them tested and they tested fine. My battery was weak, so I replaced my battery and the neg. battery cable because it was frayed. Next was the fuel filter that didn't fix the problem either. I took it to the local GM dealership and they couldn't track down the problem. I'm running out of options at this point. Is it the computer? Is there any way to test it? Any other suggestions? I have been screwing with this for a month and I don't know what to do with it

computer is possible, only good test is a swap test (same with module the testers don't work never have) do you get a check engine light? Can you flash the codes (should get a code 12 first if not the computer is bad)

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Steve
'97 GTP VS cam, ZZP PCM, and not much else yet

The engine light isn't on, and when we tried to pull the codes nothing showed up.

coil packs and the icm, my '92 did the same thing and new coilpacks and new icm fixed it and hasnt happened since

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Dan Johnston
1992 Grand Prix SE 3.1L

I took mine to a dealer to check my icm and coils too, they said they were fine, but they were bad, if you can try swapping out each coilpack with a different one if you have one lying around and see if that helps

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Dan Johnston
1992 Grand Prix SE 3.1L

Will all three coil packs go out at the same time or will one coil pack cause this problem?

Not likely, but I didnt want to take the time to determine which one was bad so I replaced the whole thing..After I looked at the old ones it looked like one of the coils was original (still had the number markings), and the other two had been replaced at some point.

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Dan Johnston
1992 Grand Prix SE 3.1L

Does it sound more like a computer problem or the coil packs and ignition module? Niether one is cheap so I'd hate to do the wrong one.

see about some used ones, the coil packs with icm sell for about $30 then if that fixes it buy the new ones

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Steve
'97 GTP VS cam, ZZP PCM, and not much else yet

Where can I get some used ones? Anyone have some sitting around that they want to sell?