Low Idle Speeds & Stalling w202

[poitin]

I have a 1996 C220 (W202) and am having some problems.

When I come to a stop (e.g. stop sign), the engine will begin idleing rough and the RPMs will fall to around 500. At times, shifting into neutral and revving the engine will cure the symptoms, at other times, after revving the car will stall. (Turning off the ignition and) restarting the car will stop the problems for a time. This doesn't happen every time I come to a stop, nor does it seem to be dependent on engine temperture or outdoor temps. I only rarely have received a Check Engine Light and this generally comes on during steady driving with no other symptoms. I don't have the best code reader. Once or twice I received a "PO50 - Idle Control Valve" code, but as of late, I am unable to read a code.

I suspect it may be the MAS or the ICV but am not certain how to test them. Any suggestions on the cause of the problem or how to test the components will certainly be appreciated. Thanks in advance.

[BenzOnline]

mostlikely MAS sensor.

[poitin]

I got another C.E.L. tonight. The code was P0505. How would I go about testing to determine if the MAS is bad or if it's something else? Thx

[BenzOnline]

What does your car do when you try to use the kickdown? Does it buckle and doesnt increase speed? Mine did that with the bad mas....just no power.

[poitin]

It runs fine other than the idle problem. I haven't noticed a loss of power or hesitation and acceleration is normal. Gas mileage is fine as well.