I have a 99 cummins with a 2001 motor and auto tranny. The motor and tranny as well as the vp44 have 35000 miles on it. It also has a air dog 150 .. here is my problem... between 50 and 58 miles an hoir my truck surges or serches for what gear it needs to be in when its not under a load if i turn the over drive off it does it 10 miles an hour lower than when in over drive ... i have 35 inch tires and just got the spedo recalibrated before i had that done it would serch or surge for gears at 50 to 58 miles an hpur which in actual speed was 60 to 68 miles per hour. Now that the spedo is correct it is still at 50 to 58 miles an hour which is actual speed ... im lost!!! I hear tps i hear tpps i dont know where to go. Thanks for all the help Josh!

 

You can start simple and try to reset your APPS can be your TPS there known to cause problems.

 

Ive un hook both negative cables for about ten mins then hooked them back up keyed it on pushed the pedal to the flood then turned the key off then started the truck but no luck. How much is a tps any way?

 

On Pure Diesel Power its $219 and $214 at autozone. Im not even gonna look on napa I despise napa, at least where I live but im one of their best customers because they the closet parts house.

 

So the way i did it shouldve reset the apps then? Thank you for all your help btw

 

That is an APPS relearn procedure. A reset will do you more good, followed by a relearn. Search for APPS reset, and you'll find a few procedures.

You can try a lock up switch to see if that eliminates it:
http://www.tstproducts.com/Torque%20...p%20Switch.pdf


If your APPS is gone, Timbo is a popular unit.