so, I have an 86 f150 xlt with a 302 efi. I have been fighting this Demond for 6 months. Too no avail. It start great when cold. Runs great. Drive to normal operating temp, cut off, cranks but will not start. Let it set for 10mins, fires right up. I have seen similar posts like this but here's where mine differs. My symptoms are changing. Now sometimes it will shut off while running. Won't start till it cools down which makes many friends at intersections. And now it's begun "lurching" like it's not getting spark. Won't go or idle up or anything and it does this spiratically. When it lurches it begins backfiring through intake. It has gotten to doing it so bad now when I feel it lurch I know it's time to find a place to pull over. It's about to cut off. I am a very experienced and capable mechanic but this one has me baffled. Here is what I have done and tests I have done.
1. Replaced fuel pump thinking it was fuel problem
2. Replaced bad connector at coil and cleaned ground contacts on coil mounting bracket.
3. When key is cycled on I hear no fuel pumps
4. Using spark plug tester I am getting fire when it won't start but seems a bit light to me compared to when it's running.
5. Replaced all relays
It will crank fine just will not start. I was thinking bad icm but my test today showed me I am getting spark. Could it still be icm ? Why don't I hear fuel pumps? When truck is. Running fine it doesn't sound or feel like timing is off. I pulled 10,000 lbs of lumber and truck had no power problems. Could it be a wire breaking down and losing ohms when it gets hot ? Any help would be greatly appreciated. Old "Beast" has pulled many chevrolets home but NEVER has one pulled beast home. I fear very soon it may come to that. Please help me keep beasts dignity.

 

It could be a lot of things, just like you said. My personal suspicion is the ignition module, I'd remove it and take it to a parts store where it can be tested. BUT these things are known to fail when hot, the engine will restart once it cools down - until such time as the thing totally fails and then you're SOL until you replace it.

Just because you think you're "getting spark" doesn't mean you're getting the right amount of spark at the right times; the pickup coil in the distributor instructs the module when to fire the coil.

Being a computer-controlled EFI engine, have you pulled the codes yet?