Engine/Transmission (1998.5 - 2002) erratic fuel pressure

[HookMeUp]

Has anyone seen this senario, I have a gauge prefilter that reads a constant 20psi. I have an electric gauge in the cab that reads the pressure at the fitting on the VP44. It will read 20psi when i first startup and then slowly fall to 12 psi and run erracticaly from then on. I replaced the sender, but still have the same results.

 

[RolandJ]

It may be the vibration from the motor and pressure fluctuation. You prob need to and a snubber into the fitting and then the sending unit. That was my prob anyway its a cheap fix before the sinding unit goes...