My 1997 has a fuel (gas) smell. The smell comes and goes while driving. The harder I drive the car the stronger it gets. I can only smell it when the top is down, or when the windows are open. If the top and windows are closed I smell nothing? If the car is parked then i can smell it inside the closed interior as well as in the trunk. It also seams to be a stronger smell on the drivers side while driving. What can this problem be?