You essentially have two separate ignition systems post ignition module, each firing 4 cylinders. You can lose the coil, coil wire (unlikely to have complete failure), cap and /or rotor on one side and still have an engine that runs but with very low power like you describe. Additionally you can have a failure in the ignition module that can fail to fire one side.

I'd start by pulling either side coil wire from the distributor cap and checking for spark. Spark on both sides means check the caps and rotors. Spark missing from one side means check the coils. They are a PITA to get to but you could swap them and see if the problem follows the coil. If the same side fails to make spark with a known good coil then the module is suspect.

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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