I have a 1992 Chevy Silverado 5.7L 350 TBI, that has an intermittent start. Sometimes I will go out and it fires right up but more likely it will not start. If I hit it with a shot of starting fluid it will fire right up and run no problems. If I shut it off sometime will start right up again sometimes not. We have changed the Pickup coil, ignition coil, distributor, fuel pump relay, fuel pressure regulator,IAC and ran new grounds to the thermostat,firewall and fuel pump. Ran a pressure test on fuel pump running about 10.5psi with new fuel filter. Really starting to be a pain in the a**. Please help