2006 Honda Civic decelerating sound

Maintenance/Repairs
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1

I hear a high pitched sound during releasing the gas pedal from acceleration (rolling mode)

It triggers usually during traffic 2-10kph with a hot weather, and then gets worse eventually if I use the brakes.

It goes away after 5-10 hours of resting the car and does not really trigger if there’s no traffic going on.

Notes:

  1. Already replaced brake pads : did not wok
  2. Had checked Air vac and hoses were okay
  3. Replaced the engine and AC fans: did not work

It sounds like

  1. someone playing a flute instrument
  2. a siren
  3. Broken speaker/mic
2

Check for vacuum leaks