My 94 Custom with 106,000 miles (shakes) while cruising at highway speeds or around 40mph. It starts fine, accelerates fine but when you are feathering the throttle to maintain speed, it shakes. No check engine light displayed. New plugs, wires are one year old, new alternator, new fuel filter, new PCV, new O2 (before Cat.), cleaned MAF sensor with appropriate cleaner and battery is 2 years old. Coil packs ohmed out OK. I did find a bad vacuum line on the fuel regulator but no help. On at least 4 occasions, the car has stalled when approaching a traffic light (related?). Starts right up and runs. It is annoying to drive with the surging, shaking, missing......

Car is an early 94, OBD 1 with 4 leads (No B). So, I can't flash the SES and my Actron 9135 won't do OBD-1.

Any suggestions?
Ray