I am having problems starting my fairly new 06 f150?

I have an 06 f150 with about 19,500 miles (i bought it with about 12,000 miles on it). Recently I have had some problems cranking it up and not sure what is going on. Sometimes I will turn the key over and it will crank, then spit, sputter and cut off (usually with some other clanky noises). Then when I turn the key over again I have to hold it for about 10 seconds before it cranks. This usually occurs after driving for a few minutes, cutting it off (to go inside a store or something) then starting back up. I'm pretty sure the original fuel filter is still in use so could it be a fuel flow problem? Where should I start?