I had the Mazda3 at the dealer for 4 years/96km service (the car is 4 years old now, but it only has 63K) and they recommended to do the "throttle body" cleaning (about $130 job). I declined the service for now until I figure out what is this all about. The manufacturer maintenance schedule doesn't mention this service item.Can anyone help with an explanation? Is this a legitimate service apart from a money making service for the dealer?Thanks in advance.