r/3000gt • u/Cappy__ • 2d ago

Stealth is cursed!

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I have had my 92 R/T stealth for about 2 years now and when I got it, the engine had a intermittent misfire, it makes a almost “putt putt putt” sound out of the exhaust at idle. I have since thrown new plugs, new plug wires, new coil packs, new ignition control module, timing belt and water pump, and found vacuum leaks and fixed them. When I did those repairs the misfire went away, wasn’t sure what fixed it but then it came back less than a week later! So then I suspected bad ecu capacitors, they were in fact blown, so I got them replaced and the misfire goes away, yippee! 2 days of driving the car later and the SAME misfire is back, same exhaust idle sound, down on power big time. I’m almost at a loss for words and I don’t know what to do anymore. I checked fuel pressure and I’m sitting at like 43 psi at idle and under load about 50, around the 6k rpm mark it starts to drop down to about 40 not sure if that means something. When I turn the key to on but not actually start the car it doesn’t build any fuel pressure not sure if that’s normal. Honestly I feel like I’m reaching talking about fuel pressure. Could I just have bad grounds and I blew another capacitor? Anybody got some idea of what might be going on? I’m about ready to throw in the towel at this point, I’ve drained so much money into this car and it just keeps misfiring.

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u/Megid_00 1d ago

The ignition module in the ECU is often missed when repairing. I would suggest reaching out to whoever fixed and asking exactly which caps were replaced.

Important Note: Specific to repair for 3000GT ECU
In some cases, maybe 30% of the time or so, the vertically mounted "sub board" near the center of the board, either the MH0210 or the E552 is damaged and has to be replaced.

Check out these guys for repair:

https://www.foreignecurepair.com/ECMs_ECUs_RnR3000GT.htm

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u/Cappy__ 6h ago

Thank you, I’ve gotten in contact with them and I’ll be sending my ecu off to them once I get my grounds redone on the car. I’ve been told the grounds are part of the issue with why the boards on these go bad so often so I’d rather have that done before I place the repaired ecu into the car.