Low idle when in drive

Hi guys, I'm kind of new here and I'd like to see how this works in a way. I guess I have a valid question as well. I got 1996 C220 and to me it seems that it idles too low when in drive. It is at 600 rpm and ocasionally it appears as if it's going to shut down when I release the brake pedal. Maybe this is normal since I am a virgin Mercedes owner and perhaps I'm not used to it. Thanks a bunch.

Without an engine in front of me I would have to say that this is pure speculation, however, many are inherent of developed restrictive idle and is a simple repair by a thorough air valve cleaning. Make especially sure that the air bleed hole has all the gum removed from it as it is likely the heart of the problem if it is the air valve. Berryman B-12 will do it (Spray). Whatever you do, don't get it in your eyes. Wear protection. it's not worth it any other way.