2000 dodge cummins, no mods except Flow-Max lift pump (150 GPH) mounted on frame w/ 3/8" line to filter and electric Autometer fuel pressure gauge connected @ IP inlet c/w steel braided hose for sensor. Truck never went below 15-PSI and idled @ 20#.After a fuel filter change, fuel gauge needle is erratic and now pressure will drop to 8-PSI. Put in another new filter things went back to normal for a few miles then went haywire again.Cracked the fuel gauge line at the VP inlet and things went back to normal again for only a few miles and back to square 1 ?????

 

If it is consistently erratic then it is time for a new pump. I would first suggest checking rubber connections and voltage to the pump. As expensive as they are the fuel pump should be the last purchase. If you have a lot of miles the pickup screen could needs a cleaning.

 

Torxhead :Thank you for taking the time to respond to my query. I seem to have found the problem, you see I have this 3/8" braided line for my autometer pressure gauge sensor (as per autometer directives) to the injection pump fuel inlet banjo bolt, (should have connected to the fuel filter outlet banjo but it would've been more trouble).
Anyway I had bled or rather cracked the line at the pump end of the braided line which only temporarily solved my problem, today I cracked the same line at the sensor end, bled it some retightened and everything went back to normal ,this time I drove it for 30 miles without any problems 17-18 PSI cruising won't go below 16-PSI needle steady as a rock, no more air stuck in the braided line which I think the problem was.
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