Chevrolet Repair: 1992 chevy 4.3 k1500, fuel pressure gauge, vacuum lines

Question
I have a problem i hope you can help my truck will not start until you spray starting fluid into the throttle body then it runs fine until you put it into gear then it dies. i have replaced the fuel pump, mapp sensor,idle control sensor, egr valve, and i cleaned the whole throttle body and replaced all the vacuum lines i have also checked the cat converter all are in good working order it seems to be getting good fuel flow when you rev it up, but you cant see any fuel coming out when you try to start it ant ideas ???

Answer
You'll have to hook up a fuel pressure gauge to make sure you're getting the proper pressure. With the key turned to run (not start) you should get at least 10psi while the fuel pump runs for 2 seconds. While cranking you should get the same pressure. Did you check the gas filter for restrictions?

If fuel pressure is ok, the next step would be to scan the PCM data stream and check all sensor inputs. Next you'll have to see if your getting a pulse width signal to the injectors while cranking. If not you'll have to diagnose that circuit.