I own a 05 chevy cobalt and when ever i start it i can smell the gasoline But then i no longer do, however i diagnost it and there was no codes and this car use ridiculous amount of gas. I change the exhaust manifold because of and leak dew to the body of it. I check all my o2 sensors and there all in good condition but it's still does explain why it's so bad on fuel which recently started to occur. At first the was an code saying (engine lean bank 1) which leaded me to the exhaust leak so i thought that's y i had this bad fuel usage but after such repair there was no difference. Can someone help me out here?