Watch That Gas Cap
Did you know that not tightening your gas cap sufficiently can cause your check engine light to come on? I recently learned this because mine turned on and when I hookeed up a trouble code computer to my Chevrolet it showed trouble code P0455 which indicates a leak in the emission control evap system. The leak was me being a bonehead and not turning my gas cap enough. This generates the P0455 trouble code because gas fumes can leak out and that's bad emissions wise. What was funny is that the P0455 Trouble Code
means that you have a "large" emissions leak though a gas cap being loose didn't seem like all that big of a deal to me. After clearing the code my check engine light went off no more P0455.