This was not my question

Hello, a flashing engine light usually means engine misfire, unlikely related to the evaporative emissions system, of which the fuel cap is related to. Everything, though, is guess work until a proper diagnosis is performed, determining what stored trouble codes exist in the engine's computer, and then determining the best way to resolve the issue. To obtain some local help, check this link for shops near you: http://repairpal.com/chevrolet-within-10-miles-of-fort-lauderdale-florida-33322