As I stated in post #8, you cannot jump the ALDL on this car with a paper clip. THE ONLY WAY TO GET THE CODES IS TO TAKE IT TO A REPAIR FACILITY with a professional scan tool (GM tech-1 or Snap-on MT2500 for example). Without doing so, you could spend $1,000's guessing and swapping parts. IF you refuse to scan it, you might as well junk it!
To the OP, a 94 Grand Prix 3.4 takes a GM #16196709 PROM, a 95 Monte Carlo 3.4 takes a GM #16229657 (new number) or 16201690 (old OEM #) PROM. Check the PROM # in your car now, and if it isn't the 16196709, you might as well bite the bullet and order the correct PROM. If you don't, this car will never run right no matter how many parts you swap.