I had a 1977 f100 which drove me nuts before I changed the ignition switch. Occasionally it didn't seem to want to start when being cranked like it wasn't getting any spark. When I let the key turn back to the run position it would fire at the last second and remain running. It progressed to only clicking when you turned the key to start like the solenoid was bad or loose batt terminals. It eventually melted the wire that runs to the start terminal of the solenoid. I replaced the burnt wiring and it soon started clicking again. I checked/replaced batteries, solenoid, and starter and nothing seemed to fix the problem. One guy at Advance who works on these old fords said it sounded like the ignition switch was the problem. It only cost $12 for a new one and that fixed my problem.

 

I know this is an old thread and I'm not even asking the original poster a question, but the problem FMC talks about right here is the exact problem I have. I can wiggle the key and bring back power just as above, but even when the radio and stuff cut off the engine had never missed a beat. Well, today my truck cut off and would not start leaving me on side of the road (see "what have you done to your truck today" thread for that story). I'm wondering if the ignition switch could have been the culprit and not the coil?

Can a bad ignition switch make the truck die while driving down the road?

Thanks,

 

Just fixed the same problem on my 78. Got the switch from Rock Auto Parts

More Information for MOTORCRAFT SW1494 this is a Ford part and a bit pricey you could try this one
More Information for STANDARD MOTOR PRODUCTS US115

Hope this helps

Bob G