I just figured out what was wrong with my 94' e420.....the prob is that the o2 sensor is faulty........darn thing is I can't seem to find it. I spent an hour under the car looking for the spark plug looking thing by the part where the exhaust meet. Am i missing something? Please help I get my part in on friday and I need to get the car up and running for sure. I travel way to much to be with out.