Can anybody who has experience with the Pertronix or Hotspark ignition modules tell me how they usually fail. Do they tend to just die and quit working altogether or can they fail intermittently?

Our 122 has had some issues starting warm lately and I was thinking it was an issue with vaporlock. This week while driving I was also noticing the engine missing for 1/2 second or so like I had turned off the key.

On the way home from lunch, I stalled and could not restart the car. I checked for a spark and was hardly getting anything. My wife towed me home and I took another car back to work. I attempted to start the car about 4 hours later and it started right up. I was getting very strong sparks from the coil.

I'm wondering whether it is my coil or whether it is the Hot Spark failing when it gets too warm.