Help! With my 99 2500 I noticed no power up hills (happened suddenly) so changed filter (also filled the filter) & it ran fine with plenty of power for a mile or so & reverted to no power again. I installed fuel pressure gauge & it gives me 6 psi after turning on key (I can hear the LP pump run & it shuts off at 6 psi. ) I start engine & it drops to 4>5 psi but GOES TO 0 psi when throttle is pressed. If I turn key on & it goes to 6 psi but I do not start engine it will slowly drop to 0 again (after a short pause at 4 psi. ) Could this be a faulty LP pump even though I can hear it run a short time after key is turned on or perhaps a faulty overflow valve? I'm stumped & do not have a code reader. Thanks for your help!