Hi,
I am new to this forum. I am driving a 2017 Mazda 3 GVC. Recently, I hear ticking sound from the driver side front dashboard. This ticking/taping sound does not always come by and once it does, the whole driving journey will have the ticking sound off and on. I noticed the ticking/tapping sound when the engine rev. It is very irritating. Anyone encounter this? Appreciate any guru here can give some advise, what is the problem and how to rectify this . Bring to SC, they cannot detect this sound. I tried attaching a video in here, can't seems to be able to attach.

Not exactly sure whether your ticking noise is the same as the ticking noise i'm facing. Reason being, the rate of the ticking noise in my car remain relatively same regardless of engine rev and speed. If going by the analogy of the explanation you received, the faster you rev, the rate of ticking will increase.  I also received the deposit cleaner from mazda, and had no improvement on my end.

Frankly, because the engine is direct injected, almost impossible for the deposit cleaner additive to work on the carbon deposits, as the fuel spray almost never reach the back side of the intake valve (maybe minor amount when the engine is on atkinson mode; unlike traditional port injected method where the fuel is injected before the intake valve).

The mazda deposit cleaner is rather expensive and you can get cheaper equivalent alternatives (like the bardahl concentrated fuel injector cleaner). Other than cleaning the deposit using the hard labour way, the only preventative method to consider is reduce cold starting, using good quality engine oil, and avoid too much traffic jams. A periodic highway rev blasting is somewhat good as mentioned by the manager your dealt with, but it won't prevent carbon build up.

you mean you have been driving below 3k rpm alll these while?