Alright, next time you get gas reset your odometer, and fill the tank all the way up. Next time you get gas, fill the tank completely and write down how much gas you put in, and how many miles are on the trip odometer. divide the gallons of gas into the number of miles. Let us know what you get. And if you havnt done a tune up since you'v had the car it might be a good idea. New plugs, wires, cap and rotor, fuel filter, air filter, and o2 sensor.