78 f150 4 wheel drive, 351m. Too ugly to show a picture of it. I have a problem with the truck not starting sometimes. Starting easy, running and then cutting off. Ran one day long enough for me to make two trips to the dump with no problems. When it is playing the I'm not going to start game, it seems to fire when I let off the ignition switch. I have found a wire coming off the ignition switch that was frayed, fixed that. Replaced the coil wire (it was not conducting). Replaced the ignition switch, hard wired the ignition module and replaced the coil horseshoe connector. It still just craps out sometimes and then won't start. It can be cold, hot, it doesn't really matter. It is very frustrating, please help. I do not have a test light but do have a multi meter.

 

Check the plugs on the distributor.

Sometimes they fray or corrode causing intermittent running

 

Have you tried a different ignition module, This would be my first suspect.

 

do you mean the connector from the icm to the distributor, the one with the three wires?

 

my 76' had the factory electric ignition, i'm guessing the duraspark. I had some of your same problems, I fixed it with a MSD 6al ignition.

 

I had the same problem start with my 74 F100 with the duraspark electronic ignition. It turned out to be the ignition pick-up in the distributor went bad but not before taking the ignition box with it. It cost me a who woppin $53.00 to replace the pick up and box from O'reileys/Checkers.

 

Its worked perfectly since. Made the 1030mile drive front Denver, CO to south Houston, TX flawlessly.