My new 2013 Outback is rated to pull 2700 lbs. Prior to pulling a trailer I was getting 29.5 MPG measured manually doing math not using the car computer although the car computer agrred. While pulling a trailer weighing approx. 1500 lbs on the interstate I got approx. 17 mpg which I have no problem with. But I have gone through about 11 tanks of gas since and I now get 24.5 mpg every time. I have lost 5 mpg. The dealer insists the computer will relearn over time to get me back to my original MPG. This sounds silly. The sensors in the car know instantly want the load is. Subaru cust. ser. had offered no intelligent input except to say take it to the dealer. Does anyone have any ideas. The car has about 6000 miles on it.