My 1999 Ford F-150 dies after running for about 30 seconds. Runs fine until then. Has new plugs and wires, fuel filter, air filter, main fuse under hood for fuel relay.
When it died on the HWY and the truck was warm you had to floor the gas to get it too start. Now that it is cold you do not it starts with it turning over then dies after 30 seconds. The engine is a 4.2 liter V6 260000 miles.

 

While it's idling whack the IAC with a wrench repeatedly and see if that makes it idle right and not stall. The IAC is like a 2 inch silver cylinder bolted to the intake right near the throttle body, that's what lets air into the intake while the throttle plate is closed, and a lot of times they go bad and stop letting the air flow, or get all blocked up. You can unbolt it and try cleaning it with gum cutter or carb cleaner as well.