My 1996 TS has been overheating for months, only kept cool by having the low speed fan permanently on, by bridging the contacts on the sensor plug (only early ones apparently used a screw in radiator sensor).
Today I think I have finally solved it. I took out and cleaned the maf sensor using maplins switch cleaner. I also disconnected the battery for a while. When I started it up it idled properly again, so I went for a drive, and the temperature on the guage was lower than it had been, so I removed the fan switch bridge and connected it properly.
After idling for a few minutes the temp reached 90, and the fan kicked in for a few seconds....perfect again.
In summary, a dirty maf seemed to be messing up the ecu settings, causing rough idling and overheating.
Just a thought