I have a 99 ram diesel we tow with,the other night the pedal went dead.the truck idled good just no pedal.I change fuel filter and put on a new lift pump,The truck started right up and ran great.parked it overnight went to start the next day and pedal was dead again.I got a p1689 code and I know what it means as far as the comunication issue.I've swaped relays no change.Again truck starts right up and idles normal but wont rev over 1400 rpms.It doesn't give a bad apps code but could it still be the problem or a wiring issue?

 

you can check your grounds on the drivers side... make sure all the wiring harnesses are tight. Other than that it is likely either a dead brain in the injection pump, or an ECM issue.

what kind of fuel pressure do you normally see driving down the road?

idle psi?
cruise psi?
WOT (Wide Open Throttle) psi?

 

The truck is mostly stock I dont have a fuel pressure gauge in the truck.If checking the grounds and connection dont do it Ill check the fuel pressure,THANKS for the info