Thanks to a posting on this forum, I replaced the TPS on my 92 F150, and saw a dramatic improvement in how the truck shifts. 90% of the time it now shifts like a dream. (92 F150 4x4 with 5.0 V8 and 4pd auto)
But every once in a while, for no apparent reason, it shifts hard again. RPM's go way up before it decides to shift, and when it finally does, it slams into gear so hard it gives me whiplash. When it acts up, it affects all gears.
Am I looking at a TPS problem again, or is there something else I should be looking at? Any suggestions or advice would be appreciated. Thanks

 

I don't know which tranny you have, but if it has a vacuum modulator, you might want to replace it.

 

Get the trans code off the sticker in the driver's doorjamb, and then compare it to Adrian's sticky in the transmission forum.

 

My Door Jam says Code E, so according to Adrian's Sticky that is a 4EOD. Doesn't that thing have an electronic Modulator? Maybe that's my problem?
Have also read other posts and troubleshooting guides that say the shift is controlled in part by the MAP, IAT, and Mass Air Flow Sensors. Maybe I should try them first?
If anyone has experience with which of the sensors or controllers would be the most likely culprit, I'd appreciate the advice. Thanks