Elec woes, crank, no start after running then parked.

Was setting timing today in shop. Fired up great, idled nice. Started taking readings for timing and after 20 minutes of idle time, under hood tach went wonky(same thing last year with 273). So I checked a few things. Didn't touch anything(left key in run) 1.Chkd coil +ve to gnd with test light, and power there.
2.Disconnected BR and it ohm'd at 1.6.
3.Put timing light on coil wire leading to dist cap(no light/spark) when cranking. BUT light/spark when turning key off/on 95% of time.
4.Jumpered BR with it still connected, crank but no start.
5.Tap test with dist connector(harness side), spark every time.
6.Replaced ECU(SMP LX101) with used 4120505, no change.

Bad coil?