Looking after your car can not only help improve fuel economy a little, but is important for safety and the longevity of your vehicle.According to the EPA having your car properly tuned can improve gas mileage by up to 4%, properly inflating tires can help as much as 3% and using the correct oil is good for up to 2%.Essentially you want to make sure your car is rolling smoothly and combusting fuel efficiently. Bad wheel alignment, an under inflated tire, dirty filters or a dodgy spark plug can let your vehicle down but are easy to fix.