Hey fellow 2gnt owners...i have recently acquired a 95 GS for 600, I think got a great deal because it has headers, 3" gst catback, and intake, short shifter, dropzone coilovers, and kyb struts.I've been having problems with it running smoothly. I have done some extensive mechanical work to it, but it very much seems like there is an electrical problem...but I am not giving up on it.

It all started the first time i drove it home i notice the constant hesitation, it sounded like it was running on three cylinders, even though it starts right up when i turn the key, the idle is high, like at 1500, all throughout the power band, it struggles then it springs back into action around 5500 until red line....it's like some boot-leg version of v-tec, lol but anyways with all my experiences with the 420a, i figured that it needed some wires, spark plugs, and/or a coil pack. So i changed the coil pack with a brand new one, got new spark plugs and wires, and the problem eased up a little but still very apparent. So then I wanted to see if the o2 sensor and coolant temp was working properly so i unplugged the o2 sensor and coolant temp sensor, the car ran great, very preppy and just like any other healthy 420a, i was puzzled, i took drove it around the block and right before i got back to the house, oil started shooting from the valve cover nozzle, then it over heated and shut off. The engine seized. So i pull of the head and i discovered that i could pick off a chunk from piston #4, so i figured that the ring landing had broken.

From there I got a newer engine with 90000 miles installed it and plugged everything up and it is the same problem. So i changed the tps, iac, cam and crank postion sensors, o2 sensor, coolant sensor, map sensor, basically all the sensors,and problem persist. I checked the codes and said that the timing was off and the the o2 sensor was bad. So i checked the timing, and bought another new o2 sensor just to make sure. and the problem still persist.
I am kinda thinking that its the ECU. Only because my last 420a was a 95 talon, and i had that problem were it would fluctuate 500 rpms when there was about 25% percent throttle, i fixed that with just changing the ecu.

So now i think its time that i present this problem to you guys. My only opportunity to pull the codes again is this weekend but ill get them and post them...Maybe its a ground or something. Does a weak alternator give these problems? Has anyone ever experience this problem? Is there some things i haven't check that i need to?

Thanks

Have you thoroughly checked all the wiring inside the shroud near the EGR tube? Very common area for wiring damage due to the heat of the tube.

Yes, i almost forgot, I actually inspected the whole wiring harness, pulled the shrouds and inspected all the wiring. The only spliced wire is the wires for the o2 sensor.