A few random things to consider -
- shoot a timing light at the crank pulley, and blip the throttle. There should be smooth advance or retard with engine vacuum (this one has the ignition module on the passenger side, with the vacuum line to it, right? My '88 did) If the timing mark jumps erratically, suspect failed rubber in the harmonic damper ("dampener" to some). Make sure the vacuum line to the ignition module isn't cracked or plugged.
- this one's a long shot, but if you're pulling power the engine is reacting by moving in the roll axis against the engine mounts. Any chance that wiring is being compromised (stretched, grounded?) by that motion?
- if you have a good digital multimeter, run the test leads from the O2 sensor wire and ground into the car so you as passenger can observe the O2 sensor output as the car is driven. Problems in fuel delivery might show up this way.
- likewise, clip the DMM leads to the battery and observe the system voltage as the car is driven. Could be revealing.
- check ALL the grounds - battery to block & the intake manifold ground in particular, for integrity and low resistance.
- with the engine off, grab the exhaust pipe downstream of the cat and shake it laterally. Any loose sounds from inside the cat? A failed core can shift and block the exhaust outlet, but this kills power (short of stalling the engine) rather than making it buck.

From first-hand experience, a jumped tooth or 2 on the timing belt just limits power and doesn't cause bucking. Just won't rev like normal, under load or even in neutral. I doubt that's the problem.

From 2500 miles distant (but a former resident of Litchfield Co.) the seat of my pants says there's an electrical power interruption - either to fuel pumps, ECU, or ignition, in descending order of likelihood.

Press on, Rob!

--
In God We Trust. Everyone else, keep your hands where I can see them.