suginami,
i have a 96 c280, and i just checked under the hood...it is obd 2.

guys,
got my car back, and my mechanic said there is misfire in one of the cylinders. he replaced all the plugs and coil(s). not sure how many coils he replaced and if he put new wires as well.

car is running okay now. thanks for your inputs.

enjoy the weekend.