anyone had similar to this, had the car about six weeks average mpg behaved like s type only changing slowly over trip time,now and i don't remember altering any settings it behaves like instantaneous mpg on my s type ie changing with throttle application more or less instantly,although this feature is not supposed to be on these cars i beleive, and it does not appear to be malfunctioning as it does go up and down with more or less throttle application i am now officially mystified.