Update:

I think I found my problem.

While searching for vacuum line leaks, I took a peak at the throttle butterfly plate. With the car off, it doesn tno close off the opening but sits at an angle...about 30 degree or so. I'm pretty sure thew butterfly should be at a fully closed position..I think.

Now..the question is, do I need a whole throttle assembly?

__________________
1997 Silver AMG C36
OEM Advantegarde Grille
OEM Clear Corners
W210 Blinking mirrors
Eibach/Bilstein Combo
Zender Rear Lip Spoiler