The E220 is not imported to the USA, so I am not aware of what engine you have in the car. My E320 has the inline six fitted with double overhead cams producing about 215 horsepower. If your E220 is fitted with another engine, then the problems may be caused by something other than on mine.
For the E320, there are two known issues with the engine. The first was that, for whatever reason, head gaskets leak; usually from an oil passage. The second issue that is indemick with this engine is failures in the engine wiring harness.
My car has suffered both problems. When the wiring harness shorted out, it took out the MAF sensor, which causes an extremely rough idle and stalling, and rendered the car essentially undriveable.
On the other hand, the 2.3 four cylinder engine fitted to my 190E has been around many years, and is a very strong engine. Since the fuel management systems on the two cars are not the same, you can not necessarily find that symptoms on one car indicate the same problem as on the other.
My current stalling problem is with the 2.3 four, not the six cylinder motor.