I store my truck from Nov to March and this year when I took it out I noticed that the fuel pressure was dropping more the normal. I have had 2 separate times that I was letting it idle while unloading it I noticed that the idle sounded different. The last time it happened I was going back to move it and there was no lift pump pressure. I shut it down and then bumped the starter to see if the pump would run and it did with 17 pounds at a idle (18 to a dead motor). I have also noticed that the fuel pressure drops almost 2 pounds more this year under hard acceleration. Being that the pump has been on there for at least 7 years I just bought a new one ( fass ddrp 02). Changed pre and post filters and then the pump with no change. I took it for a drive again today and in 4th gear rolled WOT and when it hit 2900 RPM the fuel pressure dropped quickly to 10 PSI and I let up before got lower. I know that I don't have a sock on the fuel tank module because it was gone when I removed it 2 years ago because the float fell off. I am at a loss as what to do next other then a big line kit. The only other thing that I can imagine would be a IP going bad or is it normal to dump fuel pressure when you hit the defuelig RPM which I had never done before but it came up faster then I expected.

Edited August 2, 20205 yr by Nekkedbob

Change your fuel filters?

Yes the pre lift pump filter and the main filter mounted on the block It was the first thing I did as they had been on for about 20k miles.