Yesterday morning it was -16*F outside and my truck was not plugged in After cycling the glow plugs several times I decided to give it a shot at starting- cranked it over for a while, got close but wouldn't fire. When I turned the key off, I could hear a hissing sound from around the fuel pump area (my CCV vent isn't too far away from this spot either). I've noticed it a couple of times when the truck cranks but won't fire. Is this air coming out of the fuel lines? And if it is, I assume that hearing air come out means fuel could also be leaking out though I've not noticed any fuel drips anywhere. Air coming out of the CCV? Other suggestions on what might cause this?

 

its probly the ccv