Jeep is a '96 Automatic 4.0 2WD.

After replacing a lengthy list of parts for other mechanical reasons, now there's a new problem. The jeep will drive & run perfect for around 20 miles or so of varied speeds, stop & go, small hills, etc. But after this distance, I'll start to decelerate to come to a stop, it will shift down the gears as it normally would, but then won't shift out of 2nd upon accelerating after the stop. But then, I'll park it, turn it off, restart it, and it will shift fine. It's done this the last 2 times I've driven it. I'm hoping it's a small (cheap) fix, and hoping you guys on here will have some suggestions. Thanks for your help. Here's a list of parts that have been replaced within the last 10 months or so. But in those 10 months, it has been driven VERY little due to the issues mentioned.

TPS
Alternator
Battery
Battery cables
Plugs/wires/distributor cap
Water pump/thermostat
Fuel pump & filter
Air filter
Cleaned throttle body & IAC sensor
Radiator was removed & boiled out, no leaks found

 

Reinstall the old TPS and see what happens.

 

If it is symptomatic, then you turn it off and back on and it's NOT symptomatic, this sounds to be electrical, not mechanical.

If it has the exact same symptoms with two different throttle position sensors, I think I'd try a salvage yard transmission control module (TCM). Should be relatively easy to find one and a salvage yard unit shouldn't break the bank.

 

Yeah it's done it with two different TPS's. And yea turning it off & back on seems to temporarily clear up whatever the problem is.

 

Ever check codes yet ?

 

Just did the key trick right now and got code 35, which is "35 Cooling fan relay circuit open or shorted
OR
35 idle switch motor fault - check connection"

Would either of those cause the shifting problem?