Your mileage may vary - and how!

Chrysler says the four-wheel drive diesel version of the Jeep Liberty gets 22 mpg in the city. Consumer Reports tested it and found it got more like 11 mpg.

Honda claims its hybrid Civic sedan gets 48 mpg in the city. Consumer Reports found it only gets 26 mpg -- a 46 percent difference.

Chevy's Trailblazer EXT four-wheel drive is supposed to get 15 mpg in the city. For Consumer Reports, it was 9 mpg.

'It's an unrealistic sales and marketing tool that they are actually using. They are saying you're going to get 35 mpg, and you're really only going to get 21,' Champion said."

Pain At The Pump: Government Gas Secrets - Yahoo! News