A few weeks ago my fuel pump went out on my 3.1 V6. I replaced the fuel pump and also replaced the fuel filter. Also replaced the black plastic valve by the charcoal canistor that goes to the fuel line month before. Its been ok since except for this new issue that popped up.

After I drive around for a while on a very warm day(90-100 degrees), shut off the car, let it sit for a 1/2 hour, and shortly after I start the car, the engine will die or almost die if I drive and keep the RPM around 1000-1500. If I give the car some throttle just once, like punch it to 2500 rpm while driving, engine runs fine and never has trouble after that at any rpm or speed. I also hear the fuel pump whine loudly only before I hit the throttle and after that it is quiet. The issue seems to happen more when the fuel tank gets below 1/2 tank.

Any ideas? I know the fuel pump is new but doesn't mean it isn't in great shape. Maybe fuel pressure regulator or IAC? Maybe there is pressure built up in the tank from the heat and goes away after I punch the throttle?

 

Went ahead and replaced the fuel pump since it was under warranty still from o'reilly's. Also decided to buy their most expensive one they had instead of the cheapest one. Been searching on TGO and this seems to be a common problem. If this doesn't fix it then will probably put in a LS1 plastic tank like I did on my other thirdgen.