M104.942 HFM question on idle speed
 

I realize that my E280's idle speed has risen to 800-900 rpm after a throttle body cleaning. It goes back to normal range, i.e. around 700 rpm once in D, and just surges to 800 -900 rpm when shifted to N. Is there anything wrong with my M104.942?

Another question is that M104 is significantly noisier that my 300E's M103, the noise seems to be coming from the cam's sprocket and the intake manifold. Do you M104 users have the same concern?