I have a 2002 dually automatic with 94,000 miles on the truck. That is not a misprint. I have ninety four thousand miles on the truck. I am experiencing a “flat spot” while in OD between 50 and 58 miles per hour. While driving up a gentle incline with cruise control, the truck does not get “the message” to give the engine more fuel. If left on its own, the truck will shift into drive and then accelerate to maintain the set cruse speed. Under the same scenario, if I press down on the accelerator, there is no increase in speed. The engine does not respond to me pressing down on the accelerator. If I wait a few moments and then press the accelerator again the truck responds in a normal manner.

This problem has happened without using cruise control.

Once I experienced this same flat spot problem in drive at about 25 miles an hour pulling out of a rest area on the interstate.

Does anyone know what is causing this problem? I have changed the fuel filter. I have had preventive maintenance on the transmission and rear end performed at the appropriate intervals. Someone at work suggested that the sending unit in the rear end is bad. Any KNOWLEDGEFULL insight is appreciated.

 

I beleve i had the same problem as you. It was my vp44. look here https://www.dieseltruckresource.com/...threadid=16207
Hope this helps

Kevin