3.6L 2LT here. I get around 22-23 MPG on mine. If you're only getting 18, I wouldn't immediately resort to taking it in and have a dealership look at it. Maybe its just your driving habits? Do you have AWD? turn off the Auto stop/start feature often? I've been using the AWD on mine lately and turn off the auto stop/start but I also drive it pretty gently since there's snow/ice in my neck of the woods this time of year.