Is car giving check light?Try kixx or total synthetic oils.Which grade oil r u using currently.Check spark plugs,air filter,fuel filter,service throttle body,clean maf sensor with maf cleaner spray only don't use WD-40,clean fuel injectors.If giving check light get the car scanned and check for trouble codes with OBD-2 scanner.It should give 9 in city and 13 long as I have heard from people.