Hi,

Have you checked the voltage coming out of the 02 sensor?

Search the archives for this one.

Also, time and poor gas quality will take its toll on 02 sensors.

Another item might be the engine temp sensor. I have a 300E and it's sensitive to both of these items.

Not sure if your car has fault codes but it's worth a check to see if you are getting any codes.

X/11 port on the left front fender on my car.

Good luck,