99 F 150 4.6 Engine. Usually when started in the AM it cranks and starts fine, but after it sets for a few hours, it cranks fine but is hard to start. If I let off the key and try it again it fires right up. We are talking like 3 to 4 seconds. I put a fuel pressure gauge on it and it has around 5 psi key on engine off and about 30 when running.Pulling off the vacuum on the fuel pressure regulator the pressure rises maybe 7-9 psi. Regulator did not appear to have any fuel in it. When turning off engine the pressure goes down to 0 in about a minute. The fuel filter has been changed fairly recently as this problem has been ongoing for some time. The filter change did not make any difference. Revving the engine made the psi go down a couple psi at 2,000 RPM. The vehicle drives fine normally no check engine lights and has about 108,000 miles and no stalling issues. Cleaned the MAS and Throttle Body and while it was a little dirty, no help for the hard starting. What are your thoughts Fuel Pump?