Re: 2013 5.7L ECO mode...
You have no actual ECO button on center stack, right? I think the 13's only have the ECO light which is simply informing you that you "are driving in a fuel efficient manner". The 14's like mine have a "real" ECO mode that automatically upshifts early, downshifts late, etc... to improve fuel economy. It can be defeated by pressing the button off or slapping the shifter backwards into sport mode but cannot be defaulted to OFF. Pretty sure that's a CAFE fuel sipping thing.