Sounds like a bad ignition switch. Swapping it out shouldn't hard with the proper tools.
Before you decide to throw parts at it check the connections under the power distribution center for corrosion. I have seen several of these trucks with similar problems, make sure to look for loose wires as well.
Bare Bones Offroad
Originally Posted by RookieMT
sorry I don't work on fords I park on top of them!