I drive a 1998 E39 523SE manual (petrol, 100k miles). Mostly urban driving with occasional motorway and rural outings. My OBC says 24.7 mpg. This seems low from what I've read elsewhere. I'm wondering if it's my driving style which is causing such low mpg. I'm a cautious driver, not slow, but not aggressive either. I tend to change up gears at about 3000rpm or so.
I hear that engines are more effiicient at higher revs so maybe I shouldn't change up so early? Would this improve my mpg, or is it already as good as it gets?