Hi Andy,Thanks for the reply, A mechanic near by me whom i know quiet well had the same problem and tried bosch sensors and the emissions were still the same.He then got genuine ones and it fixed the problem.It seems crazy to me I'd imagine they're the same sensor but I heard horror stories about this model of Merc regarding emissions,when you put the sensors in you have to drive the car for 200 miles and then reset the adaptations before the emissions come right. I was just wondering had anyone else come across this scenario.Also I checked for oil contamination at the sensor connectors but all seems ok.
Dominic.