Hi guy's well after lots of reading and head scratching im still confused so time to ask the grand masters ie you lot. If someone has had the same thing and i have missed it im really sorry also im in the uk so parts take time and my local mechanic aint got a clue about American stuff. When cold pulls like a train gets warmer runs worse. Dissmantled the throttle body cleaned everything put it back together appears better but here goes with the problem. the car is low on fuel but not empty ( 91 Z28 tpi engine code 8) from cold drive normal and behaves floor it the car screams to about 70 mph then it dies back off the gas revs pick up and it drives ok again. All things point to fuel starvation but i dont no. When its hot it dose the same but continues to run like a bag of s**t then dies. let it go cold then it runs again. I dont have a fuel pressure gauge but when the pump primes it comes out the fuel line like a fire hose but carnt do this when it's running or when hot. Please help as i getting really fed up starting to wish i stuck with carbs lol

Well just a question to be sure i got this strait your saying this problem happens when your low of fuel not empty just low correct? Or does this happen all the time? Also any check engine codes? Without a fuel pressure gauge it will be kinda hard to diagnose something like this if it is a fuel delivery problem beyond guessing and installing parts with a prayer that it fix the problem. At that rate though it would probably be cheaper to buy the gauge unless you got lucky.

I finally diagnosed it down to the injectors. waiting for new ones to be delivered.

There's also a chance that if it only does it when it is low on fuel, the gauge is off and you think you have more fuel than you do. In that case, it sucks air and starves for fuel as it spits and sputters perhaps?

when you had this problem did your motor want to stall in the high rpms but idle fine in the lows ? I am currently having a fuel pressure problem it holds 40psi at idle but when high revved the pressure will drop to 20psi. It seems like my fuel pressure regulator vacuum still works, because when i disconnect it the pressure will raise up. I was wondering if you had the same problem?

Mine turned out to be injectors had failed. Sorry i carn't be of any help