I had a problem with having a heavy foot on my trip so I guess that would affect the mileage. I did go over 2k frequently. I was getting on it uphill to see what it could do on the highway. I have never had it re-calibrated for the bigger tires, not sure if the previous owner did. I was disappointed with the mileage though. Given my set up on the truck, is that a "normal" mpg to expect?