I sold a friend of mine a 86 745Ti and lately our friendship is strained. The car will run fine for a while and then his wife complains of it dying on her. I drove it yesterday all over town and it was fine till it happened. The tach jumps up and down, dies to 0 RPM and then back to normal. Once it starts, it only gets worse (I barely got it home after numerous failures at highway speed). Have replaced distributor, voltage amplifier, knock sensor, (all with used parts, but the symptoms remain the same) and done the basic tune up stuff. The ignition switch seems to be staying on since the idiot ligts don't come on till it is fully stalled. It has to be in the primary ignition somewhere and I am leaning toward the ECM. Anybody seen this before?