I finally got to put the truck to work for the first time on a 500 mile round trip pull since i ran the extreme diesel fuel system cleaner through the system fuel psi is still good 13 psi at 2500 and 9 psi at 3000 rpm so I think what ever was gumming the lift pump up the cleaner removed before I tried the additive fuel psi would drop to 5 any time I ran the engine above 2000 rpm