Mystery cut out F150

While engine is at operating temp, driving at highway speed, engine shuts off. Putting truck into neutral, then turning key…no response (not even starter). Gauges and lights are all on. After a few tries, engine starts and runs normally. Dealer not able to replicated problem. No codes present. No TSB’s according to Ford dealer. Engine stoppage happened about 6 times on a 15 mile trip, and became more frequent the farther I drove. 2005 model with 47,000 miles.

Check for power (12 volts) from the ignition switch to the starter solenoid; and ignition system (coil); and other engine systems.