Torque Converter releases when going highway speeds

I have a problem that started about three weeks ago. I will be going a steady speed above 30 MPH and then my torque converter releases and the engine starts revving to high RPMs.

If I let off the gas it will go back to normal in a few seconds or sometimes I just power through it until the converter catches again (depending on the traffic I am in). I am suspecting that the TPS is going bad (which sucks because I replaced it 5 years ago)

Its a 1990 XJ 4.0 4x4 with 260,000 miles. This has been my daily driver for the last 8 years and I have done all the maintenance/repairs myself. I cleaned the IAC and am about to go through my yearly "pass emissions" tune-up where I plan to take off the throttle body and clean it along with replacing the O2 sensor, cap, wires, and plugs.

Between work and school I will not have any time to look at it until Saturday so I thought I would get others input on it.

1. check tranny fliud (sounds stupid but...)
2. break out the Ohmmeter check the TPS for a clean sweep with no dead spots (on both the ECU and TCU connectors.)

Thanks for your response yuppiexj.

I should have mentioned that I did check the Tranny fluid and it was ok. I was suspecting this too because it started around the time of my last oil change (and I decided to try a place closer to my house instead of the place I have been faithfully using all these years).

The fluid level was 1/2 between the markers.
I'll put a voltmeter on it when I can.

Solved!

I finally got some time to check the TPS. Put a voltmeter on the wires and the input was 4.66 and output was 4.25. When I tried to adjust the output down it would go crazy and fluctuate all kinds of voltages..

I ran to Autozone and picked up a TPS for 72.99. Put it in and adjusted it to 3.85 (83% of 4.66).

Now I am wondering how long the other one has been going bad. My XJ shifts smoother and has power that I have not seen for at least 2 1/2 years. Plus it is idling smoother. Hopefully I can get the gas mileage back up to 300 miles per tank instead of the 210 I have been getting lately.

Now on to the emissions test!

Its all about manual override.

http://www.steve88xj.com/aw4

:wave1: