You say you are getting normal MPG on the highway?
Check the brakes.
I worked on a Grand Am once that got horrible city mileage, but normal on the highway.
It ended up being a caliper was locking up every time you stepped on the brakes.
But after a few minutes, it would release.
So driving on the highway, it was normal.
But driving in town, where you have to use the brakes all the time, the caliper was constantly causing a dragging on the wheels.
Tuesday, July 7th, 2009 AT 10:14 PM