Gasoline smell...

Maybe your fuel pump is weeping by the pumps vent hole.
Jeff

Where there is the small of gas, there is often an associated wet-spot or stain.

I'd carefully inspect the visible surfaces of the tank and pick-up point. Obviously any area that connections exist is a potential spot. I tend to agree with Jeff that starting at the top of the tank makes sense if it is full-fill related.

Good luck,

I had the smell in my garage as well after filling up, then all week. After sniffing around I found it was the vent tube. It was just a little wet maybe from slight over fill? So I tested it by plugging it, and next day no smell. Of course I un-plugged it again, but at least I knew where it was coming from (left no stain or nothin, just slight gas on the inside of the tube).