help! gas leak

today my 01 tahoe started leaking gas pretty bad. only when it is running though.
does anyone know what this is? it looks like a fuel line and wiring harness conects to it. its above the read diff next to the tank. thanks

I dont know, but man I wouldnt drive that thing till you got it fixed. Gas running over electrical is a disaster waiting to happen. When/if it shorts it will spark, when it sparks you are in trouble.

well i assume that it a emissions canister vent valve. my only guess as to why it would have fuel coming out of it is my full tank and being parked on a hill at the time. it hasnt done it since