With the info given by dnult, Pdquick & the trickster, damn good info, by the way, my 2 cents is this:
The PROM is protected by its controller. The controller does just that , controls everything by instruction/decision from the PROM. Whatever controller you use, (must have the same part number as orig), I suggest to start from ground zero.
Clean battery posts and clamps. Clean ground connections. Make sure the alt BAT wire is in good shape. Now, since you've cleaned, ECM memory should be dumped and clean. So now you can start over with the troubleshooting process.
Start the car, let it warm up to operating temp and let it run alittle longer, maybe even takeit for a 4-6 mile cruise. Come back to the driveway and if its still revving, look for a vacuum leak, carb cleaner, WD-40, etc will work. Check hoses, brake master vac, A/C vacuum line going into the firewall, PCV valve & its hose, you get the idea. Make sure the intake track, hoses, are in good order, no holes or splits from the air scoop thru the AFM 9if equipped) to the throttle plates.
If no vacuum leaks found, then with key off, jumper the ALDL connector pins A to B. Turn key to ign, engine off. Several events will happen.
1. Codes will appear at CHECK ENGINE light, look for Code 12, i.e., pause flash pause flash flash pause. This code suggests ECM can communicate. Other codes will appear in their order. Copy them down. Then ECM will repeat codes.
2. IAC motor seats itself to plug the air hole in Throttle body.
3. EGR solenoid energizes to allow a vacuum pump, such as a hand pump, to test and open the EGR valve. This checks the diapharm, but not the seat/needle on the exhaust side.
4. Cannister solenoid energizes for purging of same.
5. After t/s, don't forget to turn off ign and remove jumper.
The above checks the controller side of the ECM. Getting back to the codes, when one looks up a code definition, it gives an area to look into. It might be its control side is hosed, broken wire from ECM to the device, or device itself is bad. Or control side may work fine, but, the function side is hosed, such as an EGR valve, it moves up & down, but there is dirt or a hole on the needle and seat keeping it open to produce a vacuum leak.
Just try keep your thoughts straight when troubleshooting. If you have a TPI equipped engine, it mif=ght be the EGR valve malfunctioned. I have read its a pain to get replaced.
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