BADSAK

I have a 2001 Legacy GT that s normally garage kept but sat out in 0 degree weather over a weekend. When it returned to the garage we noticed the smell. I have been all over the fuel system looking for leaks or any visual dampness with none to be found. In the Garage the smell was noticeable in general. During driving it seemed to drift in from the air intake as yours seemed to. Was anything ever resolved as to the culprit?