I'd agree to at least peek inside the ECU. Then I'd try a replacement distributor (junkyard, ebay or get one from someone here - I have one if you need it). If you haven't replaced the coil assembly (including the power transistor) I'd try a complete swap (again from the junkyard, etc).

It's sounding like ECU/TDC sensor/coil/power transistor, but the TPS should be within spec also.

Frank

'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum