The 2005 Chevrolet Colorado is available as a 2-door, 3-seat regular side. Starting at $17,550, the 2005 Chevrolet Colorado Base w/Z71 Off-Road 4x2 Regular Cab is powered by a 2.8L , 4 -cylinder engine mated to a manual transmission that returns an EPA estimated 21-mpg in the city and 27-mpg on the highway. The top of the line 2005ChevroletColoradoFleet 4x2 Extended Cab , priced at $ 16,790 , is powered by a 2.8L , 4 - cylinder engine mated to a manual transmission that returns an EPA estimated 21-mpg in the city and 27-mpg on the highway.