herb

i just returned from a trip to MO. (1200 miles round trip)---had a new lift pump installed in Mar and have been showing a constant 12 lbs on my fuel pressure gauge since the new pump.
in the past few weeks i began to notice a "flutter" in the gauge (in fact could hear it). after leaving on this trip the gauge started going from 12 lbs t0 3 lbs fluttering until it finally just quit fluttering and stayed at 3 lbs.
by now i am convinced my lift pump has took a dump and so called cummins in GR and they gave me a contact number in Ft Wayne where i stopped. of course they were too busy to get me in until the first of the week, but after listening to what it was doing the service mgr. suggested i change the fuel filter I changed it and walla, up to a steady 16 pounds ! That lasted for about 20 miles and bingo right back to same thing again.
now i am thinking i must have some bad fuel so i stop at a truck stop and they recomend using their PFF (supposed to remove water. tried it---no workee.
next morning before i start truck i change another fuel filter, again great for about 20 miles and back to same .
in a capsule i changed 3 fuel filters there and back, truck runs great and gauge is still wacky. would like to think it is the gauge but the momentary fix when i change filters has me baffled?

Clunk

I don't like how your pump is acting, not very steady.
How does the hidden gooseneck hitch work? I have a yellow handle sticking out from the drivers side rear inner fender and a stuck ball in the bed?

crobtex

When my fp was reading high, low, high, low, etc, it was a bad fuel pump. If you are convienced it is the gage, rig a temp gage for comparison.

herb

mine just did that to me when i went down to get my new gooseneck trailer. i had a guy there push it up and down while i held the handle all the way out and it came up. havent checked it yet--could need lubing or there is a spring i think in there that helps push up the ball.