95 Blazer 4.3 Vortex

My blazer starts then shuts off, pump the gas at start up it will run at a higher rpm. Recent tune up and I tested the fuel pump and regulator, they're good. Can it be a coil or madulator going bad?

What engine and what is the fuel pressure readings?
Any check engine lights or security lights?
Does it run like 2 seconds and the shut down?

Its a 4.3 Vortex it holds 62 lbs for about two seconds and then drops to 20 lbs. Does it ever time. Took off plemuim and passenger side looks washed, had someone turn on key several times and there is no signs of leaks and I don't see any gas laying in there. Do u think maybe its a problem with the fuel pump?

Its a 4.3 Vortex it holds 62 lbs for about two seconds and then drops to 20 lbs. Does it ever time. Took off plemuim and passenger side looks washed, had someone turn on key several times and there is no signs of leaks and I don't see any gas laying in there. Do u think maybe its a problem with the fuel pump?

The fuel pressure is leaking off or the fuel pump is bad.
Block off return line and check for full pump pressure and leak down.
Full pump pressure should be around 95 or more lbs of pressure and hold pressure with return line blocked off or at fuel filter in line.
If not your fuel pump is bad.
Good Luck