1996 C1500 won't start until I try a few times or put gas in the carb

I have a 1996 C1500 that won't start unless I try a few times or put gas or
starter fluid in the carb. After it starts it runs great, and I can turn it off and on
again no problem as long as it doesn't sit for too long.  I've recently replaced
the distributor cap and rotor, plugs and wires, fuel pump and fuel filter. Not
sure where to go from here.