I have a 2002 4.6. My problem is when I turn over the ignition, it just turns over and doesnt start until like the fifth of sixth try. It runs fine afterwards, just hard to start. Sometimes, it idles up and down for awhile before settling down.

 

I'd check the fuel system, pump/filter/ect.

 

is it when u just turned it off on a hot day? thats generally from fuel vapor in the fuel rails. or fuel filter is clogged.