My 2000 with a 5.3 has a hard start issue. It cranks fine and finally starts and runs fine. I think it is not holding fuel presure while it is sitting. Wondering where the check valve is. Is it in the fuel pump or the regulator?

 

my last bosses company truck was just like that, try leaving the key on ON for 3-5 sec. before cranking it over, this lets the pressure build up.