I have a 1983, F-150, 302, 2 bbl, automatic it will run fine then just stop. This may happen once every few days or 20 to 30 times in one day. when it stops its loses power sometimes backfires out the carb if I hit the gas, other times it will backfire out the exoust. I have to stop shut off the engine for about a minuit and it will restart and run fine till it happens again. I have had it happen 27 times on a 21 mile trip to work. I have had it checked by two different mechanics and they can not find the problem. Both times it ran fine for a few days after they looked at it.
since this started I have replaced the coil, ignition modual (twice), voltage regulator, EGR, rebuilt the carb, checked for vacume leaks, distributer cap, rotor, spark plug wires, plugs, battery, and alternator Please Help I have run out of ideas and quickly running out of money.

I hate to ask you but could you tell me wich ignition system you have??
Duraspark II or the Duraspark III???
#1 Try replacing the starter relay.
#2 Check the vacum line running from the brake booster to the intake/carb. It could be losing vacum when dropping from high tack to low Idol.
#3 I'll get back to you in just a min.

Duraspark II, Checked the line to the brakes and it is fine, Starter relay is new

Ok well I can only think of two things left.
#1 Have you inspected the cap that clips onto the coil?? The two wire's that lead into it may not be tightly connected. Or the cap could be slightly cracked.
#2 Either there is a break somewhere in your wiring system or your ignition switch. Another thing I just though of. You said you replace the distributor "cap" if you did only the cap, It could be the whole distributor. I've read the "hanyes repair manual" try'in to figure this out, But I'm not coming up with much. I'm sorry I can't help you more than this. You've done everything that I would have done. :)

One more thing. The manual claim's that if the "Ballast Resistor" is damaged in any way that it could cause a break in the current while the key switch is in the "RUN" position. This wire is located starting from the key switch to the "bat" wire on the cap that clips to the coil. However it is a specific length of special wire located inside a wire harness of the passenger's compartment.
In other words it's the wire that feed's the main current to the ignition coil while your driving.
I hope this stuff is helping you and wish you luck.:dupe::sorry::dunno:

Found the problem at last. The bushing in the distributor that holds the Stator pickup was worn out and was letting the pick up hit the armature. Metal shavings had built up on the stator. Put a new distributor in and it has been fine for several days, runs like a new truck. Thanks for the help.