This is a common problem, the CPU learns the shifting/timing from the or maybe it forgets since out on the open road not much shifting is taking place.
It's actually doing a 1-3 upshift, if you take off fairly quick and then let-off it jumping into 3rd. Wham!!! At least my was, it only took me 2 1/2 years to convince the closed mined service manager it had a problem. It would never do it for them.
Then I found TSB 98-15-3, software timing change and a re-calibrated Servo. (no tear down the servo is the one you can see on the bottm of the ATX case).
Funny the dealer then had 5-6 cars to do.
It still gets confused but not that heavy slam.
Paul
98 Mystique LS (07/97)
DMD
