I have a 2004 Nissan Xterra 3.3. I was filling my gas tank and i noticed a puddle of gas on the ground. I got home and checked under my car and found a little canister with two hoses coming from it and the canister was leaking. I sent a picture to a friend, and he said it was a vapor canister. So my question is why would I be getting fuel into my vapor canister? Should I just change it or does something else cause this issue?