Truck Repair: 2004 Cummings Problem, dodge engines, fuel regulator

Question
I have an '04 2500 4x4 Cummings.  When going interstate speeds I have experienced a sudden loss then return to full power.  The check engine light comes on and produces a code of P0251.  Dealer can not figure out the problem.  Has happened to me twice in the past week.  Have you seen this before or have any ideas?

Answer
We dont get to work on the new Dodge engines because they changed the electronics for Dodge.We dont have anything that will hook up to or talk to the ECM on a Common rail ISB Dodge.I bought a wiring diagram/fault card for a regular ISB to see if it had that code & they are not the same.Im going to call rep & see if Cummins makes one for the new Dodge.
WAS TOLD TO REPLACE A FUEL REGULATOR BY THE INJECTION PUMP.