I have a 2007 Tahoe with 110k miles. when it sits in the garage overnight you can smell a "loud" gas smell, and when I go to crank it first thing in the morning it turns over several times before it will crank. When I crank it the rest of the day its fine. I took it to a shop today and they said there is a gas leak on the top of the tank. Can anyone tell me what this might be?:uhoh2: