Yeah 40 is about the average. It was about that last winter too so I know its not due to the weather.
It has had a 'clean cycle' at the dealers to remove sulfur buildup in the cat and went back in for something replacing, not sure was, something about nitrox?
Anyway, each time i got it back the mpg crept back up to around 40 but then slowly dropped back to around 33 and its doing it again.
I'm going to see how it goes over the next few fill ups and take it back in if it doesnt improve.
If you're not living on the edge, you're taking up too much space.