RE: V6 3.8L 2002 Camaro - hissing from cold-start injector
 

Alright, so I am back with two codes being returned from the system:

P0171 - System too Lean (Bank1) and
P0174 - System too Lean (Bank2)

So it's got too much oxygen in the exhaust... That gives merit to the vacuum leak idea, plus the hissing sound... So it is probably a safe bet that there is a leak somewhere. Well, let me test this thing out and see if there is one... posting results soon.