starting problems

finally got the rig to start, at first it will start fine and fast idle up just fine at cold start run a few seconds and die, will restart but on feathering the gas pedal it coughs and pops thru the intake, sounds like timing, but for the fact that at 1st cold start it runs good. could the fuel pressure valve be the culprit in this? the rig is a 1994 trooper LS 3.2 DOHC. thanks. hope some-one has an idea.