Hiya all, I'm posting in the correct thread after posting in oil levels, it's to do with the top grade fuel versus supermarket fuel, my plan last Thursday was to drive 380 miles on a full tank of asda petrol and see if it was much different to shell v power. Anyway I normally use v power, so when the day came I realised I still had over half a tank of v power, so I just topped up with 29 ltrs of asda fuel, didn't reset avg consumption. Well the asda fuel was 99.7 a litre, at bridge of dee aberdeen, when I needed to refuel on the m6, I put in BP ultimate it was £1.25+ a litre, and the avg comp was still reading 38mpg at the time, so at £1.12 a gallon dearer meaning you can get a extra litre of the supermarket fuel it kind of negates any milage bonus of using the dearer fuel. Obviously motorway forecourt prices are the dearest but sometimes people do have to use them. I'm no longer going to mess or experiment, one thing I have realised having this car for near on 4 years is how good the consumption is up to 70 mph, but any faster it dips really quickly.