The dealership cannot find a problem as to why the light keeps coming on, but it does.
The check engine light has been on for a year, dealership doesn't know how to fix it. on 2006 Chevrolet Cobalt SS
My car has did this, it turned out to be an issue with the variable valve timing. i think they had to change one of the injectors. Not sure if this is your issue, but it sounds similar to what mine did. occasionally does it shift hard into gear? has the traction control light ever come on for no reason?
Do know the fault code that is causing the Check Engine Light to come on in your 2006 Chevrolet Cobalt? It is hard to be of any help without knowing the fault code.