I just picked up a 1992 Cutlass Ciera from an old guy
Dealer maintained, sat for two years before I got it. Didn't have much gas, but I filled it up and used some Seafoam.
So far, I've replaced the crankshaft possition sensor, spark plugs and wires, coolant temperature sensor, PCV valve, air filter, fuel filter, cleaned MAF sensor, IAC valve and throttle body (all with the appropriate cleaners), oxygen sensor, TPS.
The idle is up and down, almost like it'* going to stall. And sometimes on acceleration, it will hesitate briefly, just for like quarter of a second, and then continue to rev. And on the highway--especially while decelerating--the car will buck and stumble, but then be perfectly fine for 30 minutes.
I do have a check engine light from doing the TPS. I used a voltmeter and set it to about 0.55 volts with the throttle plate closed. The car has great power now, and it hasn't stalled out on me yet. But I really want to figure out the idle and funny bucking issues. It'* a great car otherwise.
Would unplugging the battery reset the ECU and fix the sensors? I have not once unplugged it since I got the car. The CEL only came on after messing with the oxygen sensor, CTS, and TPS at the same time, so it could be for any of those sensors I guess. The CEL goes off if I accelerate, but comes back when I let off the gas.