car only runs rough while idle on 1995 Mercedes-Benz S500

My 1995 S500 with 96000 miles runs rough while idle. While driving it seems to run fine. I have changed plugs,wires,rotors,dist. caps,coils,oxygen sensor and it still runs rough,can you help me, Thanks Ed

by in Dekalb, IL on May 15, 2009
3 answers 1 comment
ANSWER by on May 22, 2009
You could have a vacuum leak or a defective Air Flow Sensor. I would have the codes retrieved and properly diagnosed. Also have a compression test to verify that the cylinders are ok with good compression. If you can't find the vacuum leak , use a smoke machine to pin point the leak. This is a job for a Pro shop that Knows German cars.
COMMENT by on July 07, 2010
My s500 95 model with 76500 miles.The doors will not Vacum shut.When I remove the fuse & put it back,it works for a while & again it goes off.Can you advice????
ANSWER by on July 10, 2010
fuel preasure regulator
ANSWER by on August 04, 2010
I had this problem. It's your ETA, Electronic Throttle Actuator. You ASR light will eventually come and the car will go into limp home mode. Really sucks to have this problem. It's also a very expensive problem to get fixed. If you buy the part at German Star in Arizona, and have Mecedes install it, you'll save around $500.

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