91 Chevy Silverado starting problems?

[OLD DRAGONS GUARDIAN]

I recently had a friend give me her husbands 91 Silverado 4x4 with the 5.7 liter Vortec engine that had been sitting for 2 years. This truck has 28,000 original miles on it and when I first brought it home it would start on the first crank. I drove it 2000 miles with no problems but now it takes 3 or 4 tries to get it to start. I wait for the fuel pump solenoid to click before cranking it and have to do this 3 to 4 times before it will start, and if I let it sit for half an hour or so I have to do the same thing again. I've had different people tell me that it's the fuel filter, the fuel pump, a check valve in the carb, or maybe it's in the electronic ignition system, so I have no idea where to start looking.

This truck looks like it just rolled off the showroom floor and I really don't want to make things worse so any help would be very much appreciated.

Thanks