Think about the tests that i gave you. The distributor toggled the 5 volts right? Ok so this signal goes to the MPI control unit which in turn supplies a small voltage the the base of a NPN transistor in the power module. You state that when you performed the transistor test, the coil fired. That means the power transistor and coil are good. Your problem is either in the wiring from dist.to the MPI or MPI to power transistor or simply a bad MPI control unit. A am basing this on what your test results. Good luck

Over the hill but still climbing.
88 Montero 2.6L auto, manual hubs, cooling fan conversion gps,recurved distributor,LSD Diff.