How much is "significantly lower"? Some lower is normal, but it depends on too many things to tell you ~xx~ mileage is okay, but ~nn~ mileage is not. Mine gets about 35 MPG average, since I've owned it. That's probably 90% city, 10% highway. But mine's a stick, so if yours is an automatic, your city mileage should be lower. I look forward to taking mine on a 100% highway run to see what it'd get on the road. The most I've ever done with mine on an interstate is about 60-75 miles at a time, which isn't even 1/4 of a tank.