2005 5.3 fuel pressure question

Truck almost will never start on the first try unless I turn the key on and wait about 5-10 seconds,then it will start.If I try to start on the first time it will just crank over and then the second time it starts the way it should.It sounds like the fuel pressure is bleeding off somewhere and the pump has to build up the pressure again in order to supply the injectors.Any help would be great.

You need to hook up a fuel pressure gauge and check key on pressure and then engine cranking pressure and watch for fast leak down.
Also jumper fuel pump and see if it goes up to and hold specs.
Make sure engine cranking is up to specs.
Post back fuel pressure readings.
Lot of problem with the 5.3 fuel pressure regulators.
Pull vacuum line and check for gas in it.

Thats what it sounds like. You can pull the vacuum hose off of the fuel pressure regulator located on the fuel rail. If fuel comes out of the regulator you found your problem.