Pontiac Repair: 94 Pontiac Grand Prix heavy miss, fuel pressure gauge, fuel pressure regulator

Question
Good Day!

I have a 94 Pontiac Grand Prix with a heavy miss. If the car is cold, it runs great. But if I were to drive it around till it was warm and then turn it off and let it sit for 30 min, it runs like a toilet when I start it up again. It misses at any RPM, and misses bad enough that it won't idle. Once it's cold again, I can start it up and blow out the cylinders and it runs good again. I checked the plugs and wires, cleaned the throttle body and idle air control valve. I even did a compression test when it was hot and it passed. I also checked for vaccum leaks. When it misses, it's running VERY rich- my clothes stink if I am standing any where near it. Sincere thanks for your help!

Answer
Hi there:

what engine is in this? 3100 V6? I would get a fuel pressure gauge on the engine and see what the gauge reads once your turn the key off. it should hold pressure and slowly bleed off after sitting say an hour or so. If it bleeds of fasy then you have a fuel pressure regulator issue of the check valve in the pump is bad. If the fuel rail looses pressure when the engine is hot it will cause a vapor lock and cause the condition you mentione here.. Also che the regulator to make sure that there is no RAW fuel in the vaccum line if so the regulator is bad. That is where I would start looking on this. good luck :)