Mercedes: surging idle 1991 190E 2.6, mercedes benz 190e, mercedes benz club

Question
I have a 1991 190E 2.6 with 61,768 miles.  The nearest major
city to me is Chicago. I was wondering what causes a surging
idle when the car is first started or after driving the car and
putting in park?  

Answer
Answer:
You are describing what sounds like two issues, start up idle, and hot/no load idle.
I will give you three possible issues, though there are many others.
* Vacuum leak, possible cause: leaking Breather Hose, Cold Start Valve O-Ring, E.H.A. Valve Seal, Fuel Distributor O-Ring, Fuel Injector Seal, Idle Control Valve, Throttle Body Gasket, intake manifold gasket.
* Fuel pressure fluctuation on start up, possible cause: Fuel Accumulator, one of your two Fuel Pumps going bad, Fuel Pump Check Valve.
* MB Wiring Harness Failure    http://www.mercedesshop.com/shopforum/showthread.php?p=927185

My best advice:
Contact the Chicagoland Section of the Mercedes-Benz Club of America
http://www.mbclub.com/
they can offer hands on help, and have a good list of local shops that can fix your car correctly.

Here is another list of possible repair shops.
Illinois
http://www.mercedesshop.com/shopforum/forumdisplay.php?f=44


Vehicle: 1991 Mercedes Benz 190E 2.6
Part: Breather Hose
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   Breather Hose
From valve cover to intake manifold.      
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   Breather Hose
From idle speed actuator to intake manifold.      
------------------------------------
   Breather Hose
From air duct to idle speed actuator.      
------------------------------------
   Breather Hose
From valve cover to air filter housing.  

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