pig rig
+1y
you can check your fuel pressure
turn your key on and you'll hear the pump come on and go off (it only takes a couple of seconds to pressure up )then at the valve stem deal on the back side of your intake manifold push that with a pen,a screwdriver, or what ever if it blows gas every where you got fuel if it only trickles out there you go
Its not accuret but its effective
is your engine a vortec if so I'd pull the plenom off your intake and check your injecters and see if one has sprung a leak
if one is leaking or if your fuel regulator is leaking it will blow gas all over in the plenom and it will Idle fine untill you give it gas then it will drop cylinders fowl plugs and run like shot
I know I've had this problem and I wish I was there it would make it a lot easyer give me your phone # and I'll call ya