2000 GMC Jimmy Fuel Pressure

I have a 4.3 6cyl 2000 Gmc Jimmy it dosen't want to start unless I spray starter fluid down the throttle body. As soon as it starts it runs fine until you shut it off. Then you have to do the same thing all over again. I tested the fuel pressure it is 52psi with only the key on and engin not running. The pressure drops to 0 psi after 2 seconds. I don't want to pull the tank and replace the fuel pump if this is not the problem. Any Ideas!