Can anyone enlighten me on how the trip computer computes avg. mileage. I assumed that the mileage to the right of the trip odo. was the average mileage accrued over that trip. I have approx. 3500 miles on the car, and have not reset trip 1 since purchase, so it is a running avg of FE over the life of the car. It is at approx 38 mpg, since we have experience terrible weather since the purchase of the car..... and other reasons (spouse). I went on a 120 mile trip to my parents last weekend and got 48 mpg over that trip (figured with trip computer 2) Somehow over that trip, trip computer 1 eased from 38 mpg to 47 mpg over that trip. How could 120 miles at 48 mpg make the overall avg. for the life of the car jump so drastically? Is there a programming error??? Strangely the mileage on trip 1 is now back to around 38 after some shorter trips this week???