What would cause a strong raw gasoline odor outside of a 2002 VW Passat AWD V6, ONLY when parked and not running, and ONLY with a full gas tank of gas? Absolutely no fuel leak is detected, and there are NO fault codes. When tank get down to about 3/4, it goes away, and all is well! And I know -DON'T fill it up! I have already changed fuel filter and gas cap. The "top" vent in the filler neck is indeed closing. The smell is not under the hood or inside - only outside around the rear of the auto.