Hi Guys just wondering if i pick all of yours brian for knowledge a sec, i have an issue with my kickdown its a bit strange. ok i have my 98 c200 in s mode on the transmission and when i kickdown for overtake its changes down but will not go above 4000rpm and 60mph, i took it to my trusted merc mechanic and he read an error code of the car as 02 sensor failer and the car is running lean. Now here's the thing if i accelrate normally and i just press the pedal down quickly it pulls amazing and goes well passed 4000rpm and i can also do this shifting manually, doesnt feel like any performance issue.

So am puzzled is the o2 sensor really faulty or is it the dredded MAF sensor, has anyone else had this? Thanks