Hello, my '74 F100's got a 302 and she runs great, always has but lately after awhile of driving her and getting her up to operating temperature, she will not start back up after shut off. It's not fuel, it has plenty of fuel supply plus the filter and fuel pump is brand new. So I pulled off a plug wire and turned her over and there's no spark at all until right when you let off, it'll throw one spark at the end. And like I said, she only does this when she's all warmed up and sometimes she will even start when warmed up. It's random and very frustrating because it's hard to diagnose a problem that's not consistent. She's left me on the side of the road many times lately and I'll come back to her hours later and she'll fire right up like a champ like nothing was ever wrong. So any help would be greatly appreciated, Thanks!

 

There's only three things to swap and all are capable of failing due to heat.
First try a different dura spark ignition module. 4"x4" aluminum box on drivers inner fender,
Second a ignition coil. I say second because it's easier than the third.
Which is the pick up coil in the distributor under the rotor.
I would say the dura spark ignition box is usually the culprit.

 

Alright, going out to get a ignition module and coil right now. Hopefully one or the other cures the problem, if not, I'll change the coil in the distributor. Thank you very much!

 

A 74 could have points. Have you confirmed that you have points or electronic ignition?

 

Good catch, was it 75 or 76 they came out with the Dura spark?

Maybe it just needs a tune up of a set of points and condenser.

 

Points were standard in 73. Optional in 74. Electronic became standard in 75.

 

It's got the Electronic ignition option. Just changed out the ignition module, ignition coil, cap and rotor and threw a new set of plugs and wires on there. She runs great and I ran her for awhile around town and she's not having any problems starting back up. So I guess I'll see but hopefully the culprit was replaced. Thanks for the help!