Hey all,

I know there's tons of threads about fuel pressure, I've read plenty, but I'm still looking for a more definitive answer on my issue.

I've just replaced my fuel filter, still running low fuel pressure. Stock FPR and stock pump.

44psi at idle with FPR vac attached
54psi at idle with FPR vac detached
50psi key on, engine off
pushing the throttle doesnt bring it higher than 55psi

So, am I done with diagnosis and time to order a new pump (thinking walbro 255), or do I need to do some more digging?

This is on my '99 Sierra 5.3. No DTCs

Thanks in advance

 

I would replace the FPR, and see if that fixes your issue. If not then go with a new pump. Your pressures aren't that far off. It shouldn't get over 60 psi at WOT with a stock pump.

 

New FPR on it's way.

I left the gauge on all night and the pressure this morning was at 0, is this normal?