Was happily driving Superblue (my '94 4.0 coupe) today and yep, it happened again for the first time since getting her back from the shop almost a month ago: the transmission warning light comes on, and next thing you know she’s shifting HARD between 1-2 gears. As usual, I pull over and turn the engine off, wait a few seconds and re-start, and the glitch and light is (usually) gone until the next time it happens.

This is the very same issue that I took Superblue to the shop for back in December and the tech kept her for six months (don’t ask). B/c she is the MY pre-OBD II, there was really no way to figure out what was going on (I had already tried replacing both the ECU and the TCM) but by having the tech “pin” each of the transmission wires with his multi meter to figure out which one had a bad/loose connection in the wiring harness. He claimed he had found it and corrected the problem (to the tune of $700.00 or so, btw). So, I can’t figure out why it is happening again now, unless it is another wire or the original repair somehow came loose again (the plethora of speed bumps here in the Dallas area are murder on the rear suspension of XJSes, btw).

Taking Superblue back to the original tech is out of the question, so when I take her to another shop I would like to save time and $$ by suggesting which part of the wiring harness to look to first for the bad connection. Which would be the most likely culprit?