re: Ot mechanics: gas mileage issue

First let me start off by saying the obvious. Check your air filter. The idiots may have put a new one in backwards or you may just need a new. Also not that it would have that much difference it's worth mentioning the weight of oil they used maybe say higher than what your car needs. Although I doubt it would change it that much. Also have you checked the dip stick to see they didn't over fill it.

Now with all that being said......A FRICKING FORD FOCUS COME ON BAW GOT DAMN IT