Thanks for the info, guys. I am not sure what all of it means yet as this is a very new area for me. I actually just posted yesterday regarding how little I do on this car that is not normal wear related.

My Performance Products catalog shows an Idle Control Solenoid and an Idle Control Mirco Switch both mounting somewhere near the IP - diagram is non-specific. What do these do? Can they be the culprit?

I recently needed to replace an idle control switch on my Grand Cherokee due to similar symptoms. Essentially what this did was regulate the position of the butterfly in the throttle body in responce to airflow. Does the 2.5 have something similar?

__________________
1996 (W210) E300D 86K - Traded in for a Lexus
1992 (W124) 300D 2.5 Turbo 202K - Sold
1983 (W123) 300D, 146K - Sold
1970 280S, 263K - Sold - Beginning of addiction