when i first bought my 2000 4.4 i was getting 280 miles on a full tank (£80) this was with 95 ron petrol. i then checked the tyre pressure and used 97 ron petrol. now the computer is saying 375 miles before the next fill.

In the manual it does say to use 98 ron petrol for better performance and economy, I would have to say that on better petrol the car drives a ot better and the mpg has increased.