[s-cars] Unlocatable fuel-like smell

[Kaehly, Michael T, CMO]

I have noticed over the past week a sometimes faint/sometimes strong odor
emanating from the car (95.5 S6).  It usually occurs when the car is stopped
or after I shut her off in the garage.  I keep looking but am unable to
locate it's source - someone suggested that it could be the cat's but I
don't think it's that type of smell - sometimes it's very much like fuel and
other times I think it might be freon or brake fluid.
 
Anybody experience something similar or know what I might check?
 
Thanks All!!!
 
Michael