My truck has been a textbook full of problems. I had a P0601 "PCM" error. With it I had a ridiculous surge at highway and normal speeds. Mainly around 40, 60 & 80 mph. I removed my throttle body cleaned it completely with carb and choke cleaner. I removed the IAC (Idle Air Controller) and cleaned it. After cleaning the IAC the rough idle and surging was gone. Replacing the PCM cured the Cruise Control.

I also replaced the TPS. Did nothing for me.
My truck is running the best it ever did for me but that's after tons of little things.

 

I did the reroute thing too with new wires. DIDN'T WORK EITHER. Still surges in or out of OD.

 

There is a chance that you got a bad TPS when you replaced it. It isn't uncommon to get a bad one from the parts store. Break out the haynes manual for the test procedure and test your TPS with a multimeter to see if it has a flat spot in it.

 

I had an o2 simulator for my rear o2 sensor that made my tranny surge like you guys are describing.

 

Even if it was a TPS wouldn't changing the throttle position at the time it's surging make it stop? I've tried it and it dosen't seem to affect it.

 

I never buy autozone or other parts store sensors. I went through 3 TPS's from advanced and told them to just give me my money back. I don't usually go to the stealership for anything but sensors are something I do. It's really sad how one sensor can make your truck run like a turd. I'd actually be scared of buying a new truck and keeping it 10 years and have to replace twice as many sensors on it.

 

Good point, you would think it would be that easy. It might just be a crap sensor, test it and see.
Now that I think of it, if I hit the gas while it was surging it would just surge worse until I pushed the pedal hard enough to kick it out of overdrive.