OM116 380SL Low Idle When Warm
 

Hi all,
My SL has a low idle when she's warmed up. Usually takes driving around a bit to get her that warmed up (top of the 8). Idle in D will drop to just over 500rpm. If she sits at idle for a minute idle will slip a little and she'll stumble just a little and kick the idle back up to +/-650rpm.
Any idea what I might be looking at as a cause? ICV? That was replaced a few years ago, but I'm sure that doesn't mean it's good. Any way to kick the idle up a little? Motor was just rebuilt (and runs like a top!).
Thanks!
-m-