I am posting this for a friend of mine who bought a truck that was flood damage with a salvage title. It is an '05 drw standard trans. with 44k miles. It had water in the fuel tank, so he dropped it and cleaned it out, but doesn't know if it ran with water in the fuel lines. He drained the fuel bowl and replaced the filter too.

Throttle was surging before and now just won't start

Codes he has:
P0251 Fuel Pressure Actuator
2122 Pedal position sensor low
2127 Pedal validation switch low

Truck won't start on its own. He can put a rag damp with gas to suck the vapors in over the intake and it starts but doesn't idle well, but once running it drives/runs fine.

 

i'd say fuel pressure regulator on fuel manifold or injectors