1999 ford explorer starting problem?

[Mike]

i have a 1999 ford explorer having some trouble its a 4.0l sohc and im not sure whats wrong its one of the three things fuel pump fuel filter or fuel pressure regulator heres what it does when you turn the key and try to start it right away it will crank for about 7 secounds and then start but when i turn the key to the one postion more then once like 2 times or 3 it starts right up like it should anyone know what it is im not sure if its the fuel pump filter or fuel pressure regulater