1999 F-150 Trouble Starting

I just submitted a post concerning overreving, and maybe the two issues are connected (the first has to do with overreving). I have a 1999 F-150 with a 4.6 L V-8. I have recently replaced the spark plugs / wires and fuel filter.
Every once and a while, my truck has a hard time starting. I have to crank it for maybe 3-5 seconds before it will fire up, and once it does, it will sputter for a few seconds before it finally starts. I'm pretty sure this is due to poor fuel pressure. I am not very familiar with electronic fuel systems, so any assistance you can offer will be greatly appreciated!
Thank you!