I have an 2002 Hyundai Auto.

My car has the clicking noise under the following situations:

1) rolling in neutral with/without brake applied
2) rolling/decelerating without gas pedal pressed (I guess the same as rolling in neutral) with/without brake applied

The noise is the most noticeable when going at around 20 to 30mph, and would be gone under very low speed <5-10 mph. The weird thing is when I press the gas pedal and the car is accelerating, the noise is gone too.

My mechanics said it is because the wheel cylinder which is noisy. But I don't quite understand why the noise is gone when the car is accelerating. Any clue on that?