OIFVET

I recently bought a 1991 5.0 with a newer 89-93 gen 5.0 motor. A couple days after purchase i was driving down the street and the car shut off while sitting at a stop light, i was able to get it home after many cycles of it shutting off and turning it back on. I came to the conclusion after i heard the fuel pump go nuts after turning on the key that i had to replace it. I replaced the fuel pump(stock replacement), fuel filter, and fuel pump relay. she ran great for a few days afterwards until yesterday when i was going home thru town and it started doing the same thing, i had noticed that i was at about an 8th of a tank and figured that it was acting up due to the low fuel levels.

I thought about it later and figured it might be the fuel pressure regulator?

Note: the car had been garage kept and rarely started could this contribute to a faulty fuel system?

craig71springsport

How much a car is garaged is determined on how much you trust the other person's word. He may have taken good care of it, but could have beaten the snot out of it on the weekends. Sounds like it could possibly be electrical. When you said the pump was going crazy, was it just a loud hum/buzz? If so that's how it's supposed to sound. Could be a clog somewhere, if it really was garaged, and not full of gas, the tank could have eroded and you could be getting clumps of dirt and rust through your fuel system. OR it's really old fuel, either one is bad. Put fuel system cleaner in a half tank and bounce the back of the car good to stir it.

Another possibility is vapor lock. Vapor lock is when the fuel in the line vaporizes and can't be pumped by your pump. Are you driving your car hard, thus making high temps in your engine bay, thus leading to the possibility of vaporizing your fuel at a stop? While rare with fuel injected cars, it is not impossible.

OIFVET

I haven't driven the car hard, and when i replaced the pump i inspected the tank as best i could and i didn't seem to have any forein matter in it. Would disconnecting the vacuum line from the regulator while the car is running perhaps release the vapor lock? I purchased fuel system cleaner and used it that's when it started to drive fine after i filled the tank up the rest of the way. when i turned the car on to hear the pump prior to replacing it, it did not make the normal hum it was making a sound almost like it was shorting out or trying to pre-load it self multiple times...does that make sense? it sounded almost like multiple buzzing sounds like....buzz buzz buzz