1992 Chevy Lumina computer change
 

Hi.. I am new and hope you can help me. http://forum.doityourself.com/images/smilies/smile.gif Please forgive me if I posted it at the wrong place.
I have been having trouble with my lumina with a heavy smell of gas and using it very fast. I was told by the Chevy dealer the computer needs changed. Ok I did it myself. I got a computer off a 92 lumina 3.1 and the numbers matched. The PROM number did not. So I put my PROM in from the old computer.

The computer fixed the gas smell and the fuel mileage is a lot better. It does not sound any better (has a miss sound). Any way and new problem has arrisen. It shuts off when you slow down to stop or really slow to make a turn. Other wise is runs like a raped ape.

My question is should I have used the PROM from the old computer or should I have used the one that came with the computer since it came off the same year and model as my car? Or should I be looking else where?
Oh when it does idle or just before it dies at a stop sign it lurches (sound wise) you know kind of like it starving for air or gas, then getting it.
Thanks cj