I drove Monte Carlo, Impala, Allure, Intrepid, Grand Am etc, both are V6 3.0 - 3.2 L, relatively new car (less than two years), both about 8L on highway, and 10-12L in city. My own Buick has a supercharged 3.8L V6, about 7.1L on highway. The figure is coming from real fuel consumption.