Many thanks Notsoaverageguy,
I checked the service manual and it says:
Don´t touch the sensor.
If the sensor is out of range, change the throttle body assy
But they offer a tool to make the measurement very easy.
It´s about 20 $ for this pn: 57001-1538 - Sensor Adapter
And of course you can use it for the adjustment.
What we need now are some data/ values to find the best setting.
Manual says 1.02 V - 1.04 V at idle => section 3-47 to 3-50
I found a lot of information in a Suzuki forum as they have the same issue.
An adjustment of 0,1 V made a huge difference
As soon as the renovation of my garage is finished, I´ll gonna check my sensor values
@Ivan: I know..
That´s why mine has been flashed and it is way better. Cannot be wrong to check the correct setting of the sensor