Having starting problems with my 2001 Silverado 1500 4x4 w/5.3l. After sitting for a short while engine will crank but not start. Giving it a little throttle it will start and run fine. Stop engine and then it will resart with no hesitation. I think there is a loss of fuel rail pressure so maybe a pump, any input would help. Thanks

 

Fuel pump is gonna be my bet...or the fuel pressure regulator

 

Check valve in the fuel pump may be the problem. When the check valve goes bad the pump still works but the fuel bleeds back into the tank and no pressure is maintained. I put an inline check valve in the fuel line and that solved my problem.