I have a 2000 GMC Sierra 1500 with a 5.3L. I have every bolt on mod other than a turbo or injectors. My fuel pressure is low below 50 pound with the vaccum line to the regulator hooked up, and 60 with it unhooked. I replaced the regulator and fuel pump and filter and still have low fuel pressure. I cant seem to figure out where my problem lies. Can anybody help me?

 

maybe be a stupid question..but when was the last time u changed out the fuel filter?

 

Unbolt the bed and slide it back a few feet , pull the fuel pump and check the sock. It might be full of junk.

 

So, has it occurred to you that since you have replaced the pump, regulator, and filter, it might not be fuel related? Those pressures sound about right.

To the two of you that have already responded to this thread regarding him checking his pump sock and replacing the filter, DID you even READ his post??

 

Spec for key on, engine off is 55-62 psi.

 

Is that with the vacuum connected or disconnected?

 

Since the engine is off, it doesn't matter...

But that is also the spec for engine running with the vac hose disconnected.

 

No time reference was given.

 

How is it running? smootehr idle, no bucking under accellertation? could it be ignition related?

 

Idles good, but it has a flare out when crusing. I can hear the engine tone rise while driving and when i let off the accelerator. It kinda sounds like the engine revs up when I let off the accelerator.