Truck just started this a couple days ago. Going down the hwy, level road, the rpm's will jump up a couple hundred for a second or so, then drop back down. I think it is the torque converter unlocking. Happens in OD and D. At first it was only doing it with cruise on, now it does it with it off also.
Is the torque converter dying? Solenoid maybe? Could the check valve cause this?
I was already having problems with the converter locking up too soon, so maybe this is related?
Thanks all!

 

Does the TPS have any say in this?

 

Sounds like you need to replace your torque converter clutch solenoid. It's a $90 part. That part tells the TC when to lock and unlock.

 

Our truck did the same thing, as posted above it's probably your TPS. Very easy to change and cheap (under $20).

Chuck

 

Sounds like a classic TPS issue.

 

will try tps first, thanks!

 

I just had the same issue...TPS fixed it.