Hello everybody, I just found this forum from a benzsport posting. Looks excellent so far!! I will visit as much as possible! My newely aquired 40,000 mile C36 goes to running like a dead cylinder/misfire while I'm driving. I notice it start to do it while I am at a light waiting to go, or entering a turn and accelerating again after the turn is done. It will start running rough at the light & continue upon acceleration or after starting to accelerate from coming out of a turn it won't down shift to 1st or 2nd & will shake pretty bad!! If i kill the car & immediatly turn it back on the problem is GONE!!!! It rarely returns the same day, but give it a day or two & it's back. I'm assuming that it has to be electrical B/C of this? The dealer I bought it from was honest w/ me when I told them about it. They had the car serviced before I picked it up. They had a new coil put on(which cylinder i don't know) b/c of the same issue, and a new O2 sensor to get the car to pass a green sheet. The car was exported to and used in Mexico City. That is where it drank fuel for 6 years. To my knowledge the plugs and fuel filter have never been changed. I heard there is a recall on engine wiring harness and OVP(overvoltage protection relay). Would that have anything to do w/ it?? What about Throttle position sensor/ Throttle body issues (since the symptom accompanies a 'no downshift situation') I am starting to notice rotten smells coming from my exhaust every now and then also! This might mean that unburned fuel is killing my cat-converters??? I've never had a check engine light come on either?? Maybe my light is burned out?? detailed replies are definently welcome!! Thanks, Kyle Houston, TX

The strong odors from the exhaust means that the car is running rich. Running rich is kept in check with the O2 sensor and Mass Air Flow sensor plus many other components. Mass Airflow Sensor is probably shot and will need replacement as they lose their acuracy as time passes and they are positioned above stainless steel headers. Also, 02 sensor will need to be checked and or replaced. Both catalysts probably need to be changed and see if the 8 year warranty will cover this. First, see whether the warranty will cover this because you definitely dont want to be end up paying list prices for these cats. If the warranty doesnt cover this, take it to an MB indie. Running rich can be caused by many things but I just gave the scenario which happened to me which is the best case scenario. The dealer may be stumped by this one and will want to just throw parts at the car like $2k wiring harness which is probably causing your rough idle. Once my car had its cats changed, the service advisor said they billed Mercedes twenty hours. Low octane fuel or low quality fuel voids the emmisions warranty, by the way. I never had a check engine light, either. The CE light comes on with complete failure of a component not due to aging. Your plugs have only 40k miles on them and they wouldn't have caused this unless they failed terribly.

I think the federal warranty for catalytic is 80,000miles/8 years

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96' E320