Failing to maintain your car, including leaving a dirty air filter in your engine, often has a negative effect on your vehicles performance. Should you neglect to change it, you could experience a decrease in gas mileage, spark plug failure and engine overheating. Generally, a filter will last past its lifespan without causing these problems, but it is never a good idea to leave a dirty filter in your car for an extended period of time. Always change your filter per the manufacturer's specifications.
