Why don't we seek an Atty for a class action suit against GM for posting erroneous gas mileage? I bought this car BECAUZ 27 highway was posted. I can't get above 21 That's 30% off! I have never owned a car (at least 30, including 5 caddies) that didn't get the posted. I believe it was a known lie to sell cars! I have a 2011 Jag XJ-8L that can get 30 mpg highway it gets 23 around town. It is heavier bigger and does 0-60 under 6seconds!