I know that the
www.fueleconomy.gov website would have the fuel mileage ratings you may be looking for (from the US Govt). But you'd be able to check all sorts of model years and vehicles and see them side by side to make a better more informed decision on which vehicle is right for you. Also the 2012 model Colorado 2WD is getting 25 mpg highway and 18 mpg city. Thats with the 2.9l 4 cylinder (automatic or manual makes no difference). The 2005 Colorado 2.8l manual gets 24 mpg highway and 18 city. I hope that helps you!
Jeff Morris, Chevrolet Customer Service