1992 500sl Engine Rumble/Shake

[lymlyt]

Hello again. Question on my 92 500sl with 65k miles.
When I first start the car, it feels like the engine shakes/rumbles for the first 3-5 seconds. This happens
almost everytime i start the car, cold or hot. The
RPM is about 1000 when first started then drops to about
500/600 when warm.

If I recall correctly (?), the problem seemed to first occur
when it ws cold, but now it seems to happen when both cold
or hot.

After the first 3-5 rough seconds, the idle is very steady
and smooth, especially in gear.

Over the past 12 months, I've had new motor mounts, caps,
plugs, gas filter, and 60K mile service.

Any assistance would be greatly appreciated!!!

THANKS!