The EPA's fuel economy for 2001 Impala base is 20/30MPG. My one can get over
30 when cruising on highways. But in city driving, it has been below 17 since I acquired it a year ago. The car runs basically ok, just recently developed a kind of scraping noise upon acceleration, and I feel some loss of acceleration power. The dealer checked it, but found no problem and told me the noise could be "normal".I just have been wondering what can cause such a significant difference between city and highway driving?
Thanks.