I have a 2014 Corolla L and lately when the car idles the interior fills with the smell of gasoline. I've taken it to a mechanic and he can't find any gas leaks or exhaust leaks. I did have the cabin air filter changed and he said there is a little door on it that is missing so I have it scheduled to be fixed. But that doesn't explain the gas smell. Any ideas? It freaks me out.