Once in a while my 2002, 2500 dodge deisel looses throttle. It will do it while i am in motion as well as from a stop. I still have about 10 percent of my throttle but the other 90 percent just dissappers. I could put it to the floor and nothing changes and then it will just kick back in.

 

Your Drive-by-wire TPS is failing. You have a check engine light on?

 

Mine did that and it was the VP44 going. After I replaced that it was fine

 

check for codes, key on, off, on, off, on, and watch your odometer. 0121, 0122 it's your apps, 0216 it's your pump. If your CEL is on, it will probley be the apps, if not it's probley the pump. You can search "dead pedel" and read all about it.