That is the one I mean, yes... idle speed screw.

I am not sure I undertsand what you say... can I remove the screw, and hardly feel any difference??

My screw as I see it, activates the butterfly just a bit.. I think it makes a diffenrence on my idle.... and maybe my "idle" when braking with the engine from high speed (dont know what it is called in english ) It sounds like it is fueling a little bit in the exhaust, and gives little throttle it judder alot!!!