03 Dodge, Int Stall, Idles Ok

[THaslett]

Have an 03 R3500, engine will int stall running down highway, initially thought problem was the lift pump, fuel psi would drop to 0 and engine would stall. Replaced unit with in tank style pump kit. Fuel pressure better now, will still int stall, not near as much. Makes me believe old pump was on it's way out anyway. Truck has good power on initial acceleration but if you stay into it it falls on its face. Have checked air filter, etc. common stuff for the lack of power problem. Fuel pressure will still drop below 10 psi on long hard accel down to about 7 lbs. Other thing I found was that if I hold my hand on the injector lines from cp3 to injectors, I can feel a hard pulse on two of the six. No codes coming up of course. Had history code for ckp sensor, cleared out, poss false code, truck has stalled multiple times without resetting this code. What rail pressure readings are normal on the HO engine at wot and idle, poss pressure relief valve stuck??? HELP!