For problems with miss under load, first replace the plugs with properly gapped stock plugs.  If no fix, the problem may well be the D.I. unit.

For no start problems: Be advised that D.I. units can fail totally and without notice.  My car was running fine when I went to the grocery store, but when I came out, it wouldn't start.  The D.I. cassette had shorted internally.  Having done that, it also aggravated a corroded connector, which stopped conducting sufficient current.  The D.I. had to be replaced and the connector cleaned to get the car running again.


Do you hear the plug cleaning buzz after cranking, when the ignition is switched to OFF?  (You'll need to have someone else crank the engine and then switch it off, while you're listening at the DI unit ... some can be heard from inside the car, some cannot).

Does the tach needle bounce when cranking?

Can you see trigger pulses with a scope when cranking?