i have a 02 4.7L everytime i try to start it i haft to crank on it for about 10 or so seconds before itfinallystarts but if i turn the ignition on for 5 or so seconds then start it, it fires right up could this be a pressure regulator or the fuel pump?

 

May want to have it hooked to a fuel pressure gauge, may even be a fuel filter restricting the flow. When you turn on the key is when you get that burst of fuel to start it a pressure guage should let you see that I would think.