Accelerator sending unit remedy......maybe.

[Toolmaker51]

Vehicle is 05 F650 with 6 cylinder 5.9L turbo Cummins, 5spd auto-trans, 350k miles, 26,000gvw. Just completed a 2500 mile drive in 4 days, through Missouri, Illinois, Indiana, Ohio, West Virginia, Pennsylvania, and back diverting through Michigan and Iowa.

During latter part, [turning around] began intermittent hesitant throttle response, but not when bumping speed up via cruise control. It also initiated the "Check Engine Service" light. Like many late model vehicles, there's no mechanical connection with intake, just a potentiometer-like sensor linked to throttle plate or similar device. Cruise control doesn't involve pedal, so.....

For whatever reason, the pedal and sensor assembly is unavailable, though pictures and part numbers appear. I'll look for a switch alone if this proves effective at all; googling the switch number only leads to the assembly without mentioning it. Puzzling indeed.
So, I removed assembly to analyze how to introduce contact cleaner to what is basically a drum switch.



Pic 1 depicts drilling through outer wall at about 20°, clear of the cavity bottom, beyond 'standoffs' and through switch proper, and again from opposite diagonal position. Body thickness and logic say internally, there is a commutator not a rotor, and why deep position was chosen, about .12 up from switch face, the cavities not visible when assembled. Very easy test of rotation didn't reveal any interference with shank end of drill, of 1/16" diameter.

Pic 2 Then plugging outer holes with toothpicks, used syringe to fill one cavity while operating the barrel with 90% iso-alcohol, it drained out other side. Part way along, I hosed down the cavities to help reveal whether anything would flush from inside. That was seems inconclusive.

The switch is evaporating alcohol out now under an incandescent lamp.

[Unkle Fuzzy]

The apps (accelerator pedal position sensor) from the same year dodge 2500-3500 should fit though you may have to change the connector. It shows to be 154.79 pedal and all. https://www.rockauto.com/en/catalog/...on+sensor,5061

VW's drive by wire is an elegant hall effect unit that I have never heard of one actually failing. I have an extra because it came with an auto to manual conversion included with one of my 3 TDI Bugs. I have even swapped one once but it wasn't the issue after all.

[Toolmaker51]

The apps (accelerator pedal position sensor) from the same year dodge 2500-3500 should fit though you may have to change the connector. It shows to be 154.79 pedal and all. https://www.rockauto.com/en/catalog/...on+sensor,5061

VW's drive by wire is an elegant hall effect unit that I have never heard of one actually failing. I have an extra because it came with an auto to manual conversion included with one of my 3 TDI Bugs. I have even swapped one once but it wasn't the issue after all.

Thanks Unkle Fuzzy.
Yes. I ran cross visual matches that didn't display the connectors well enough to understand configuration used by Dodge via rockauto.com. Not been involved service wise with drive-by-wire before. Took added pics to aid continuing search. The 20917A number doesn't retrieve anything until combined with 0835 - no switch but complete assembly. Still puzzling,

and $154 is about one-fifth the expense of those shown, yet not in stock anywhere, and discontinued through Ford! 2005? Even the shop doing the work couldn't find one. The APPS is hard to find, the TPS (throttle position sensor) easier, but deemed a fault when dynoed.

After it dried out, I poked a little wad of foam rubber in each cavity to lessen dirt getting in but still be removable, reassembled and installed.
Soon going to unload the materials bought and see how she does. It's a crane truck, uses cruise control to hold throttle position running the PTO.