Throttle hang

Before you go spending all kinds of money replacing/rebuilding the pump, start with the simple. Sucking air is the #1 culprit with Cummins throttle hang. Gotta check fuel lines from tank to filter to pump...then decide. I normally remove each line, submerge in a 5 gallon bucket of water, plug one end of fuel line while applying shop air from a hose (trying to get the best seal at the inlet side as possible.) See if the line is porous if it's creating bubbles in the water. If so, replace fuel line(s).

 

Glad you found it. I always hope for the best, expect the worst and start with the simple and obvious before I start spending unnecessary $$$. Sometimes it ends up being what I was hoping it wasn't though. Good luck!