Have an unsusal fuel press drop. Key on, pump primes up to 60 psi for 3-4 sec, then stops and drops to 50 psi, then gradually drops down to about 42 psi. The FPR is newer, less than 300 miles. There does appear to be washing in the plenum on thr FPR side like before, but while cranking, the press is 60-65 psi, higher then expected. Should I replace the FPR yet again, or should i suspect another issue, maybe the CPI, at the injector tube connections, the nozzles, etc.? There is no viz evidence of leaks while the press drops, but the press drop is slow. There was fuel pooled on both sides, but only washing on the FPR side. The fuel pump is orig, CPI as well. Any ideas?

4.3L vin W 1994 Jimmy

 

You have to watch the inlet and return lines that attach to the injectors aka the "nut kit", also my problem was the pulsator in the fuel tank. It s a rubber piece to prevent vibration and noise. Due to the ethanol in the gas, they tend to deteriorate. You can replace it with a piece of rubber hose, if that's the case.

 

FPR is the first thing that came to mind, since it wont hold pressure. To double check this you could take the plenum off and hook up that fuel pump hot wire and see if it leaks.

 

Nut kits new too, changed it with the FPR b4. The press should hold 60 psi after KOEO, not drop to 50 psi after pump shuts down, correct?

 

i just had same problem it was the fuel pump silencer on the fuel pump.I took that off and attached a hose. What happens is starts to suck air about 1/4 tank.Put a presure gauge on it put the bleed hose in gas can and bleed it off with the engine running If you see air in bleed hose its in the tank.