[s-cars] fuel vapor on warm days . . .

[marc weiner]

There is a tube that runs under the passenger side of the car that vents fuel vapor on warm days . . . after a good hard run home from work my garage fills up with fuel vapor from the under side of the car.  Does this happen to anyone else . . . this really started happening a lot last summer and starting to notice it again . . . not really noticeable at all this last winter.  I am running Hoppen/Lehman stage IV software (26-27 max overboost), 8.5:1 compression pistons, RS2 turbo, RS2 extrude honed ex. manifold, RS2 injectors, Lehman modified cyl. head, Strommung 3" turbo back exhaust (mit cat), stock MAF, metal bypass valve.  I had the dealers recall done on the fuel line so that is definitely not where the vapor is coming from.  In fact I can get under the car and see the fumes coming out of the tube I decribed on a hot day.   Is the just something normal . . . I just can't believe how vaporous the garage smells and even my wife can tell it aint coming from my backside.   TIA.  
-Marc
94 Pearl White S4 with all the goodies above + Bilstein/Eibach suspension, S6+ euro brake kit w/ 323x30 rotors and stainless brake lines, 3 spoke A4/S6 sport steering wheel, ASW camber plates, Centerforce Clutch, and a whopping 212,000 miles (112,000 miles since the upgrade from Stage III to IV) ( 137k miles since stage III went on at 75,000 miles, and the suspension on for 162k miles) - car has had 3 timing belt changes to date.