Ok so i sold the black Z and now i got a 89 iroc 350 auto
heres the prob i have no power above 3000 rpm
none the motor wont even turn over 4200 it sputters so bad
i run a drive test on my scanner and when the car does this it is at full lean
so i pull out the old fuel pressure gauge and the car has 32 psi at an idle and 20 psi when i put it to the floor but when idling and i pull the vacume hose it goes to 38psi
heres the question is it the pump, the filter, or the regulator.
if it is the pump how do i know for sure...

also it has 13.8 volts at the pump at WOT

 

Could be the pump on the way out, sounds like it just doesn't keep up under load. Or the fuel filter if it's not new. And did you check the voltage at the connector, aor ideally the voltage drop while it's running on the wrie back to it?.