Sons F150 starts ok most of the time. Sometimes get in it, turn key and nothing. Starter good, took out and checked/tested; replaced solenoid and battery cables clean and tight. When it does it, no click and lights are bright and everything works. Does this model have a starter relay under the hood - could that be bad? Can go back in a couple hours and starts again.

have the battery checked 1st

Thanks to Brian (Liteliner). Called Brian and he said change the cables, not just the terminal. We replaced the positive battery harness and so far so good. I had asked my son how the battery terminals looked, he said they look good. When I saw them last night before we started replacing them I knew then what it was. The old thin spring terminal was corroded and the wire going into the crimp was also. He had already changed the negative terminal.

I had the same problem with a dodge, and it ended up being the ignition switch under the dash. It was not reading when it was in park. It was an easy fix, on the dodge.

When it acts up, try moving the shifter in and out of park.

May also try tapping on the starter, this would indicate you have a issue with the starter.

Big problem also with the shifting linkage if its a automatic. It gets loose and you can feel it in the gear shift when it does it. On the coloum under the dash is a clamp with two torx head screws that need to be tightenened from time to time happened on my 99 and 2000 model. Also if it doesnt start again go into nuetral and see if it does start, if it does check the linkage under the dash

We got the problem resolved by replacing the positive battery to starter cable. Liteliner suggested this when I called him and as usual he was right on.