I've got the same problem When I engage the starter with the key the coil goes to 0 volts. release the key to run and 12 volts comes back. turn the key to run and bump it with the solenoid and it starts. aftermarket coil and distributor no ballast resistor . My trouble started when I moved the coil near the fender.
I wish mine would drop out to 0 volts then I'd have something I could troubleshoot! Your loosing yours on the start circuit, acc2. Little different but the same suspects
The ignition switch itself
The switch connector
The bulkhead connector
The ECU connector
