I have a 2006 Cobalt LT 2.2L, 5-Speed. A few weeks ago I got a check engine light and auto zone told me it was a gas cap. I purchased a new one, put it on, unhooked the battery to turn off the light but the light came back on 56 miles later. I then took it back to autozone and they gave me a P0442 (small EVAP leak) and then reset/erased the code. For the last 4 days the light hasn't came on (150+ miles) but now I'm getting a STRONG gas smell and EXTREMELY reduced mileage. 79 miles on a half tank to be exact. I checked for leaks but nothing. Also, if i get in and try to crank it right up, it takes 4-10 seconds to start but if I turn the key to the ON position for about 1-2 seconds prior to starting, it fires right up. I am also getting a black sut from the exhaust pipe but it doesn't smoke while running. SO CONFUSED and about to drive it to NY from FL in a few days. ANY SUGGESTIONS WILL BE GREATLY APPRECIATED!!!