When I turn on the ventilator in my 2000 OB automatic, and have it set on fresh air, there is an immediate and acute gas (not exhaust as far as I know) smell. The car doesn't smell particularly gassy from the outside. When the air is put on recirculate, the smell goes away. A relative of mine who's a mechanic mentioned something about a fuel breather, but was pretty obtuse, and I don't understand how that would make a great gas smell through the ventilation system but not on the outside of the car. Any ideas anyone?