Here are my measurements at the coil terminals.
Cold
Motor off (+) 6.8v (-) 0.95v Motor running (+) 8.3v (-)3.7v <-- I expect to see this with the engine running.
Hot
(+)7.1v (-)0.9v <-- I expect to see this when the engine is NOT running. Very close to above values. ("not running" values) NORMAL.
Battery voltage is 12.5v at the battery and 10.5v before the resistor. TYPICAL. (although we'd like to see as close to 12V as possible)
There is a spark from the coil that is somewhat weak that sparks at a rate of 2-3 per second. NORMAL There is no spark at the plug. NOT NORMAL. Check wire from coil to Distributor. Check center conductor to the Rotor. Cannot be loose against the top of the rotor or frozen in place. Should spring in & out. (this is suspect!) I checked the resistor when it was hot and oddly it was showing 0 ohms. Not normally possible, the resistor should increase it's value with heat, but only by a little. (like .1 ohms max) This time, however, it restarted after only about 10 minutes. Granted though that I only let it get hot in the garage and didn't take it out on the road.
The second time, I let it get even hotter and this time there was no spark at the coil, but the same readings from the coil terminals. After cool down, spark from the coil again. How about the voltage at resistor? What happens if you quickly swap the Bosch module? (if you have a spare) No change when swapped? If no, not the module.
The coil is warm, but not hot. NORMAL It's the second coil I've tried, so I'm not sure how two coils could fail. I'm not sure what Bosch coil the second one is, but the first is a Bosch #0221122012.