Same here. I was getting great mileage in the summer, but winter has given me quite the hit, so that'll drop my lifetime mileage. Disappointing, but that's what it is.I actually hit 30 mpg on my Ranger early on. But I wanted it to be closer to my manual calculations. So I adjusted the computer settings. Now my mileage is pretty much spot on. You can read all the different settings that folks say they adjusted the computer to, but it boils down to your climate, driving conditions and the way you drive. Based on my adjusted computer and the 15,500 plus miles, I am still getting overall 24.5 mpg since I started driving the Ranger. But that's based on my driving habits, what few times I tow the trailer and the landscape/speed affecting the mileage. I can still get a little over 26 mpg on some tanks.
So for me, I am very happy with the fuel economy I get. It works for me!