I just bought the car, but before i even got it home, the engine went. I replaced the motor with one from the bone yard and it runs great... untill it dies. mostly when the rpms drop to idle, (which is kind of rough) I sometimes get 3 warning bells and the rpms will fall right off. sometimes I can keep it going by feathering the throttle. Starts right back up with no hesitation, unless it sits for a bit, sometimes it wont start again. Other times I can be driving down the road at highway speed and it will just die. Im not sure if this problem was there with the old engine or it has only developed since my engine swap. Car drives beautifully to work in the morning, but not in the afternoon with the heat and the traffic. I have changed the plugs wires and air filter, tested the coils hot and cold, changed the mass air, O2 sensor and egr (used parts) crankshaft position sensor( brand new) cleaned the battery terminals, and the ground buss (two wires were fused together on the drivers side, dont know what caused that) and I have removed the fuse and relay panel on the fire wall and cleaned and inspected every thing. I am at my wits end!!! I have a freind with a 94 ssei that is parked and he says I can use the pcm for a few days to see if thats it, will it work in my normaly aspirated engine? Please let me know any thing that might help, cause Im right out of ideas[/list]

the only thing i can think of that would be making it die in the low RPMs but lets you keep it alive with manual throttle would be your IAC. You might want to check into replacing it. But let some gearheads give you a better idea before doing anything at all.