Hi,

Thanks for your reply. As for the Audi, two bottles will do and it will not harm your o2 sensor. This is a direct injection vehicle if i am not mistaken and will be very. very beneficial to your car.

As for the MErc, it will not harm any sensors but I'm afraid to tell you that you will have to send your car to the service centre to reset the ECU from fault codes and there will be minor misfiring during threebond. Two bottles for this also. If you can accept it that you are to reset the ECU, perhaps before service; then this can be used. No harm to sensors.