Ok, I have a 93 2-wheel drive. It has 220k on it. It started to come in and out of overdrive, so I changed the tps from another motor I had sitting here. It didnt work, so I tried the pot bypass trick. It seems to be a little better, but when at highway speeds any movement in the gas pedal either accelerating or decelerating makes it downshift no matter the speed. I think that when I hit big holes or bumps it is downshifting, but not sure if its that or the pedal moving when I hit a bump? Any help will be much appreciated. Thanks ahead of time.

 

Sounds like it's got a flaky connection somewhere. Check the wiring harness down to the crank sensor, and also check the harness down to the OD solenoid and to the NSS.