Idle too low between 550-600

[markus_74]

Hello,

My car 325i has idle too low 550-600rpm and sometimes it is difficult to start and withow idle the car body feel shake.

But at 800 rpm up it feel smooth and no problem.

I have try clean icv, injector, check air hose but not found any problem.

Any idea?

Thank you
Markus

[reggid]

check throttle body switch