CLS400 O2 sensor CEL and rough idle at cold start
I have had both sensors replaced, and the contacts cleaned, but the CEL reappears after a short period of driving. The car itself feels completely fine when driving - no loss of power and very smooth. However, recently I've noticed that at cold start, as the temperature gauge is around the 60C marker, the engine shakes quite noticeably, which immediately stops once the engine warms further.
Does anyone have any idea what the issue could be? Other than the shaking at idle the car feels completely fine when driving...


