Starting but not cranking

I have a 2001 Ford Crown Victoria LX with 85,300 Miles On It. V8 4.6L. In the mornings when I go to crank the car it starts but doesn't roll over. I think it might be the fuel filter or something. It only does this when the car sits for more than a hour, I don't get it I have bought a new battery and got a new air filter, oil change and new spark plugs. It starts fine through out the day like if I go to the bank 10 minutes later I come out and it cranks right up. But when it sits for a while it never cranks on the first try and always cranks on the second try. There is no loss of power or funny sounds and it runs the same. I don't think it's the spark plugs miss firing. Can you help me figure this out Mr. Mechanics?

I have a 2001 Ford Crown Victoria LX with 85,300 Miles On It. V8 4.6L. In the mornings when I go to crank the car it starts but doesn't roll over. I think it might be the fuel filter or something. It only does this when the car sits for more than a hour, I don't get it I have bought a new battery and got a new air filter, oil change and new spark plugs. It starts fine through out the day like if I go to the bank 10 minutes later I come out and it cranks right up. But when it sits for a while it never cranks on the first try and always cranks on the second try. There is no loss of power or funny sounds and it runs the same. I don't think it's the spark plugs miss firing. Can you help me figure this out Mr. Mechanics?

I agree I need a new fuel pump, I put a new fuel filter on anyway. Thanks for the info! How long do you think I have before it goes out completely?