96 4th gen, 5spd, 92k, lightweight flywheel, spec 2 clutch, full exhaust, intake are the details of the car.

Initially, a simulator was put on the O2 on aftermarket exhaust to clear the ECU code (0707 or whatever it is). Drove from NC to FL, and this is where the problems began.

At idle, after any amount of easy or hard driving, it will slowly decrease from 800-900 all the way to 0, and the car turns off.

Ocassionally, while the car is moving, it will do the same. I'm coming from owning a OBDII 240SX, and it was very similar to my distrib. being shot. I know it doesn't have one, but could it be ignition related? Any suggestions?

 

Rear O2 sensor has nothing to do w/ fuel trims.

What other codes do you have? And by the way, this thread doesn't belong in here.