Have a 1991 Formula 350, has done this now twice..able to start and drive car. But once I stop, turn car off.. Wont start, just keeps turning over but wont run. Come back hour later or so, car starts right up, no problems. Any ideas my friends?

 

my guess would be something ignition related. maybe the ignition module?

 

Heard of many people having a similar issue due to the security chip

 

If security light isn't on while cranking,
Would def check the ign module, pickup coil and coil. Also if you have stock injs, ohm them cold then hot when the no start is present.

If light is on, look at the vats system. Common issue is the wire breaking that goes into the ign cyl.

 

Mine was doing this check the positive battery cable to the starter. If it looks a little to corodid then change it that should fix the problem. That's what my problem was other than that it would be the Vats security system wire from the switch to the wire harness. If you move your tilt steering wheel a lot you may have damaged these wire that run down the sterring colum.