in my experiance when flying round my local a roads and back streets i was getting 21 mpg and it was showing i had 120 miles left in the tank, once i hit the motorway on my trip down to the coast of 50 miles i was doing 34 mpg, by the time i got there it said i still had 109 miles in the tank??? seems to just work it all out on an average on how your driving and goes up and down. never trust it to much though as when i lent my car to my ex girlfriend and showed her the computer she ended up running out of petrol on the m25 when it was showing it still had 18 miles left. i told her to ignore the orange light and go by this :oops: oops!!
