Consider this:
the 2008 Chevy Tahoe HYBRID 2WD V8 gets ONLY 22MPG highway! that's what most of our 20 year old V6 or 4cyl 4WD Yota's get. So really if you can get as much as a brand new hybrid SUV, then there is nothing wrong at all.

 

Yea, but it's got 400 horsepower and weighs in excess of 6000lbs. It's a foot wider, three feet longer and 2000+lbs heavier. Put that same drivetrain in a 3800lb Toyota 4x4 and stay off the skinny peddle and you'd probably get 30mpg.

 

During the winter the air is heavier and smog stays lower. To reduce winter smog they put additives in the gas that reduce emmisions; however they reduce gas mileage at the same time. I can almost always tell when the summer gas blend is back. My corrolla will go from 32-33 mpg to 36-38 mpg.