bad gas mileage

Keeping your vehicle well maintain would help to get a better performance. You may find some recommendations on this page; http://www.fueleconomy.gov/feg/drive.shtml

Not sure why I am getting 29.5 MPG on mine Same model and year

get the car tuned up and also have them replace the gas filter and the fuel injection system. The Aveos were made to only go up to less than 30 mpg, no more than that. What you are getting can also be very bad gas in your car, but also that your car needs to be tuned up seriously and the fuel injection system to be replaced or cleaned out. That can be done at 30,000 or so. Check with your manual and also call your dealership to tell them of your problem.

THAT is unacceptable as the only reason to drive one of these is for the gas mileage. Having said that , does the thermostat function correctly, are your driving habits that bad ? Is the engine running poorly , with a terrible miss . Or is this engine somewhat out of time , but before I assume that I would suggest you get the vehicle scanned to determine what the engine may have as a list of trouble codes. The engine light may not work as it does not in mine. Depending on the result of a diagnosis of these potential issue a restricted exhaust would result in low vacuum and make for a fuel hungry engine. In the end it may be a good idea to run from this one.