-I drive a 2005 F-150 XLT with a 5.4L engine in it. This problem only happens after I have been running the truck on a small trip (15-20 min), stop to get something, and then 5 min later start the truck up, and this is the feedback I get.

-Sometimes it barely cranks, idles for a second and then cuts back off.
OR
-Takes much longer than usual to crank and get's going fine.

THIS IS THE ONLY TIME IT HAPPENS, UPON RESTART AFTER DRIVING FOR A SHORT PERIOD.

ANY IDEAS?