I have a 2001 F150 S/C with 5.4l and 96k miles. when running the a/c on max and fan on hi, the truck will run fine then after a few minutes it will sputter then engine will run normal for a while. Just today was driving down the highway and with no indications the truck just shut off. I pulled over to the sid eof the road, put it inpark and it started right up. What can be the problem? Please help.....

 

Welcome to the forum.
The first thing that I would do is to scan the computer for codes. Even if the "check engine" light isn't on.

 

Might want to check and clean or replace your IAC.

 

The IAC is not doing anything whenever the engine is off closed-throttle. It won't be the cause of random stalling while driving unless the stalling is taking place only at closed-throttle.

More likely, the OP is loosing either fuel pressure or spark intermittently.

Steve