For the last month, my Alfa Romeo is running different. I don't think, or hope it's not a serious issue. It has back-fired on a few occasions, and it doesn't shift as smooth,feels like engine is running harder, and struggles for a good speed. I suspect it has something to do with the fuel, it has emitted the smell of gasoline on a few occasions, and when the issue first arose, car wouldn't start right away, like it was out gas. Not sure if it's an issue with fuel, air filter, or carb. Thanks