gasoline smell

[Marc]

83' 500sl, car is running great but has aquired a gasoline smell while driving with the top down. Don't smell it all of the time. It does seem to be more frequent if driving agressively (more throttle). I have read some of the other posts on gasoline smell. This car does have the plastic expansion tank. Would this cause the smell though, since it is when the top is down and the expansion tank is behind the cabin? I would have the same question regarding the fuel filler cap. Is there anything in the engine compartment that could cause this? Injectors maybe? Since I seem to smell it more when I'm stepping on the gas. But I mention again that the car is running fine. I know it could be anything but I'm looking for common items inherent to this model.

Thanks in advance.

Marc