On a long trip to Cinci, OH I traveled about 75 MPH on the highway and averaged 21 MPG. 21!!!! Ok, intown I averaged about 15...these numbers blow compared to my Lexus. The V8 in this car is bigger, has more power, and weighs more and gets 28 MPG on the highway at that speed and 18 in the city. I average about 20 because I do both. I spend the same amount of money for gas each time I fill up, but I fill up once a week now, and not every 3 days...I hate bashing the LS, because it looks so good, and was fun to drive (when it drove right) but man...It's just a money hog.