1994 Lumina 3.1 ECM replacement

Car has intermittent rough idle....runs great at faster speeds. Took it to our local Chevy dealer they diagnosed it as a "faulty ECM" and wanted over $500 to fix it. I can order a rebuilt ECM for slightly over $100.

Temped to try this but a few questions first:

1. Where exactly is the ECM?

2. The part indicates "The PROM[s]/CALPACK must be transferred from the original module to the replacement module." it looks like it just plugs into the replacement - correct?

3. Is there any reprogramming needed once replaced?

Thanks in advance for your help.

The PCM is in the RF corner of the engine compartment.

http://www.justanswer.com/uploads/ebrock63/2007-11-14_135424_2007-11-14_134858.png

The MEMCAL is accessed through a cover on the side of the PCM. Be sure the PCM is not plugged in to the vehicle wire harnesses when exchanging the MEMCAL.

Thanks for the diagram. Is there any programming or re-programming that needs to be done once its replaced?

Thanks again.

If your ECM has a transferable PROM/Memcal, then no further programming is needed...

Thank you. Very helpful!