When it dies, did you notice if the tach dropped to zero instantly?
The tach lead comes from the coil. I have had the wiring going to the 12VDC supply to the coil go bad.
Grimy black at the push-on connector on the coil. Stripped the wire back to shiny and crimped on a new push on connector.
The wire wasn't making a good contact, bad crimp/groddy, with the connector. Metered the connector to coil; was ok, the wire at the female was toast.
Very disconcerting have the car die suddenly on the interstate...Tach would instantly drop to 0.
1986 +8 PI Vitesse 'Flapper" with 214,000 miles down the road.
