I've been tracking fuel, mileage, and all sorts of things since day one on my 04. 5. One thing I always do is pull my hours run from the speedo when I fill up. I've just crossed 37K and from the time I left the dealer's lot I've averaged 40. 3 MPH. (Total miles driven divided by hours from the meter. ) It might be interesting to see what others have and if there is a correlation between average speed and fuel mileage. My average fuel mileage from day one, including about 5K of trailer pulling, is 15. 5. Unloaded mileage is running 18. 5