Ive searched around and have not really been able to find anything on this. My O2 sensor the front passenger side one (not sure exactly what it is called) has oil on it. my rover does leak oil on to the exhaust but the problem is its getting all over my O2 sensor and i believe that is what was causing the code to be thrown. should i just replace the one or should i attempt to clean the oil off of it and hope that it did not do any damage?