My Honda is getting horrible gas mileage! I figured out the math and it only comes out to 12.5 mpg! I am only gettin 200 miles per tank and it is a 16 gallon tank. I don't know what to do. What could I change in it to make the gas mileage better? I know it needs an idler pully bad but would that really make that much of a distance in the gas mileage to bring it all the way down to 12.5 mpg? A friend of mine has the same car and his is getting 28 mpg in the city. Is it possible it could be the oxygen sensor? but would that really make the mileage this horrible? PLEASE HELP!!!