My dad came over recently with his new chevy colorado for its 1st oil change. Its an automatic, 3.5, Z71 2wheel drive, extended cab. I asked him the mileage, he stated he got 23mpg on a road trip from ohio to minnesota. He did say his previous S10, a 4.3 extended cab got 24mpg on the same trip. But his mileage might improve on the colorado with time, it still has less then 10k miles on it.