The last tank of fuel I input was definitely a full tank used so the next one will be the same as per your suggestion.As I have said on this Forum before, I just like to enjoy a journey at reasonable speed and not to become obsessed with eking-out every every last drop of fuel. I have, however, taken to "free-wheeling" a bit, recently. I am surprised how easily the car progresses with little drop in speed! And my DIS shows a slight improvement in average mpg ... I think that even if my life depended on it, I couldn't get these ultra-high mpg's! Over 80 mpg ??!! I wonder what the ideal cruising speed might be, for best mpg? 50-55 mph? That would be almost unbearable to me! The only way to accurately check the mpg is true "brim-to-brim" Maybe some mistakes might have been made in making these incredible mpg claims?
I'm now letting my wife have the car for a week to see the difference in mpg of driving styles.
I'll make sure she uses the full tank.
I have checked the cars speedo with my iPhone gps and our TomTom gps. They both read the cars speedo being 3mph slower than the seedos indicated speed.
I assume that is an acceptable tolerance?
I don't think I have made a mistake in writing down my mileage vs price paid for fuel and quantity of litres filled. I have been doing this for a while with the other vehicles I've owned but there always is room for human error.
Hopefully I am getting the mpg Roadtrip and fuelly say I'm getting, I'm not sure why having to user all of my fuel to test my true mpg matters but I'm keen to give it a shot for the sake of argument.