Ok...having some more troubles and I'm looking for advice. Since my car was worked on at the dealership, my gas mileage has been under 20mpg w/mostly city driving. Previous to it being worked on, I usually got 23-24 city and 28-30 highway. They said that they fixed a coolant sensor and a turbo valve as well as replaced the battery and fixed the heat/air blower and the rear defrost. Oh...and the heated seats. So...would any of this cause a change in my mileage? The car seems to be running fine and I checked the tire pressue. Any ideas would be appreciated!