Carl,
Did Mae Lynn's F150 have a 4.2 V-6? If so, it may be a problem common to the engine.
I have the same engine in my E150, and it develops a miss every once in awhile, but it hasn't given me an engine code yet. I should add that my wifes truck will start missing if it has been idling for several minutes, but will go away if you shut it off for a minute and restart it. I really do hate computer controls on vehicles! The old stuff was so much easier to trouble shoot.