That car is a candidate for the radiator problem that leaks antifreeze into the transmission through the cooler. This almost always causes shuddering on upshifts 1-2 and 2-3 along with other random quirks. If there are no fault codes indicating specific problems like the conductor plate the adaptations are reset and the car is driven. If the trans is better then an updated module is ordered in. If its not better then a glycol test is performed to confirm antifreeze contamination. Worst case scenario is a new radiator and transmission.

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90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff