I bought a C200 cheap recently. Lovely car and really clean and well looked after since it was first registered way back in 2003 so I'm happy. Bought it knowing there was some issues.

So... Plugged in my OBD tool and pulled the CEL codes and get an O2 Sensor (bank 1 sensor 1) failure and all cylinders with misfire codes. The MAF has recently been changed so I'm hedging my bets that the O2 sensor is all that's causing the problem.

It drives perfectly well and MPG is spot on what the book says. The only issue is that at idle the revs are erratic sometimes - not all the time though - but it will happen every time I drive it at some point in the journey - usually after about 8 to 10 miles from what I have observed.

So my question is this... if the O2 sensor is failed/failing and idle revs cause fluctuations and sometimes even to the point that it stalls (it's an automatic btw) then will this cause the misfires in the cylinders?

From everything I've read for all cylinders to misfire is usually not a problem there but somewhere else.

I've bought a new O2 sensor which I'll be fitting this weekend but whilst I'm under the car should I be checking anything else?