Pontiac Repair: fiero ecm, throttle position sensor, orielies auto parts

Question
QUESTION: I have an 88 Pontiac formula fiero with a check engine light that comes on and off on regular basis, mostly comes on when I'm not using accelerator. The codes read throttle position sensor and ECM. I replaced both, tried to learn idle, don't know what else to do without spending the big bucks at a repair shop. Any suggestions?

ANSWER: Hi Enoch:

I take it that the light is still on after the parts were replaced?? what codes are stored in the computer? The Idle learn proceedure is not hard for that car and not learning it will not cause the light to come on it will just have a very erratic idle. If you goto like auto zone,advance. Orielies auto parts stores they all offer free code scanning.

---------- FOLLOW-UP ----------

QUESTION: First, thanks for the immediate response,that was great. I did take it to advance to have scanned and they said it needed a TPS & ECM,  I put both on and the codes still tested as TPS & ECM, nothing changed. I just purchased the car so I don't know a lot of history on it but did notice a "ADS super chip" decal in the window, Is a super chip located in the ECM next to the prom? because I had to reuse those and I wonder if that could be messing with me. it runs good going down the road but when I let up on the accelerator is when the light comes on and goes off when I steady apply the accelerator. The engine also surges in park or neutral but idles more steady in gear but the service light is on until I get going down the road. THANKS!!!

Answer
Yes on those older cars the Prom and the back up fule/spark chip are inside the ecm. Some have 2 some have 1 but they need to be swapped over from the old one to the new one. As for a TP sesnor code with the key on unplug the sensor and use a volt meter you should have 1 wire with around 5 volts and one wire will be a ground. across the ground to the 5 volt wire should rwad approx 5 volts. If not you have either a feed or ground issue to the tp sensor. with the sensor plugged in back probe the ground wire to the extra wire it should be under .5 volts that is the signal wire back to the ecm. if that is good the sensor is good. You may have an issue with the signal wire back to the ecm.  You could have a bad ground to the ecm causing issues. If you have an ECM fault code still I would suspect that the prom may be bad "performance chip" Good luck trying to get the original one that went into that car being that it's 20 years old. You may have to surf the net to find fiero restoration parts dealers. Good luck :}