C32 mileage?

[Mike400E]

I am hoping other C32 owners can confirm for me the HORRIBLE mileage I am getting in my '02!? I know I am a new owner and definitely enjoying the performance and HP of the Kompressor, but I would have thought a 3.2 litre in a relatively small (Only about 3500 lbs!) and aerodynamic car would get better than 17 MPG overall.

I drive a good mix of city and highway. My old 400E averaged about 20MPG, 4.2 litre V8, 300 lbs heavier and all! On the highway, the trip computer says I get 22-23 or so, which is OK, but around town, it just plain sucks! My POS 4 litre six banger old Ford Explorer actually gets about the same mileage, with barn door aerodynamics and 700 more pounds to haul around. My understanding is that the supercharger is supposed to disengage when not being used, but I suspect it is sucking power and gas even puttering around.

Input, ideas? Thanks!