Reduced engine power

Thanks for the advice. We used the scan
tool and it read two pending codes,
PO131 and PO151. These are the same codes
that the shop read and then they replaced the two oxygen sensors. We have two choices if we replace
the PCM. Either buy a rebuilt one and have it reprogrammed ($400+) or send ours back east and
have it reprogrammed ($250+). We live in Canada
so I don't know if we could buy the PCM in the U.S.
We still don't know if replacing the PCM will cure the problem. Thanks again for any help you can give us.

So I grounded the OBD by jumping A to B and retrieved the code (42) from the blinking Check-Engine light. I stopped by my mechanic with the code. He told me it, in all probability, was the Ignition Control Module. For $38 at the local auto parts store and 30 minutes work, I replaced the ICM. It works great. The old ICM had rusted pins and the contact plate coated in crusty old silicone di-electric grease.

We have solved the problem after several months.
It turns out that the 2 Napa fuel pumps that we installed were the source of all the trouble!
My husband put the old fuel pump back on and
the car was almost back to normal.
We bought a new GM fuel pump and then installed that and the car has been working fine ever since.
Hope this will help someone else down the road
with the same problem.