Have a bit of a quandary, so here goes. My YJ sat for about a year after getting it running before making her roadworthy. Stock 4.8, Wix Corvette filter/regulator, Delphi FE0114 pump (Delco EP381 equivalent). Noticed as of late LTFT's have been a tad high (+15 to +23 depending on load), but no P0171/P0174....yet. No vacuum leaks. Have to cycle the key a couple times before starting. 40psi at the rail (should be 58-60 KOEO, 50ish running.....which it was when I first put it together and fired her up a year ago). Drops immediately to 5-10 after turning the pump off. My initial thought is the drainback valve in the pump. My fuel pressure gauge isn't long enough to reach inside the cab yet (need to extend the hose) so all tests done stationary at idle. Blocking off the return line at the regulator still yields 40psi. Deadheading the pump KOEO SHOULD raise it to 75-80, no? Blocking the pressure line after charging the system (and opening the return) will hold that 40psi almost indefinitely.....the SECOND I removed the vice grips, you could HEAR the fuel drain back into the tank, and pressure dropped to 5-10 psi. This SHOULD rule out the regulator, which do fail.....especially the cheap ones (which mine is not). A lot of people have been reporting the hose between the pump and sender have been failing, regardless of platform. I'm pretty sure I have to replace the pump, but I'm a little wishy washy on whether or not it's the regulator....as when they DO fail, you get 40 at the rail as well. Thoughts?