I have a 2003 F-150 w/ a 5.4. When cold it only takes one hit with the starter and starts. Restarting when the engine is warm, it takes two sometimes three hits with the starter till it starts. When I say hits, about 1 second intervals with the starter. The check engine light is not on. It has 105,000 miles with the original spark plugs. Engine runs and idles smoothly. The fuel filter is about 50,000 miles old. I've been putting fuel injector cleaner in gas tank every 3000 miles since I purchased truck brand new in 2003. Air filter is clean. Gas mileage hasn't changed. I disconnected the battery for about 10 minutes to reset computer. Still have warm starting problem.

 

Man, I posted a question that's even stumping the F150 Gurus here.

 

after you get it started from a cold start get it all warmed up and shut it off. go under your hood and disconnect your fuel pressure regulator vacuum hose... if its wet with gas it shouldnt be and that means you need a new fuel pressure regulator... if it isnt then let me know i'll have to think of somethin else. almost sounds like an intermittant crank sensor issue