Hi guys, I'm working on a friend's 89 F-150, V8, not sure of the engine size but I don't think it matters in my case.

Firstly, the truck feels like it's starved for fuel. When I rev it, it hesitates.

The fuel pressure sits at 30 PSI at idle (which i believe is low), and jumps up to about 35 when I hit the throttle. I have replaced the pressure regulator.

The high pressure pump is whining and just generally sounding bad. I can hear it with the truck on. It doesn't matter which tank I have selected.

Now I'd imagine that it's just a bad fuel pump, but I've heard that the tank selector switch might have something to do with it? Just hoping someone with some more experience in this area could shed some light on this for me

 

My high pressure pump is noisy when it isn't getting enough fuel, but it also could mean it's going bad. I'd make sure the reservoir is getting fuel from the tank low pressure pumps.

 

30 psi at idle is fine. my 89 hesitates at lower rpm when revving or accelerating and its a cracked exhaust mani as the culprit see if you can pull any codes(refer to sticky thread on how to pull em) good luck