Mercedes-Benz Poor Fuel Mileage


Top of the hour. Mercedes cars naturally consume more petrol than -Toyota, Honda, Mazda products etc.

My car developed an unusual noise and my local mechanic said the catalytic converter was shattered which he removed and replaced it with a muffler then the noise stopped, but later I discovered that the fuel consumption of the car has greatly increased.

So I want to know

1. What is responsible for the sudden increase in petrol consumption of my car.

2. The relationship between the catalytic converter and the fuel consumption of a car.

3. What can can be done to bring back the petrol consumption to its original state and even further reduce it to be like the Japanese cars or better.

4. What can be done to generally reduce fuel consumption of cars.




Hey there Nkere,

The only thing that really comes to mind here is now there is a change in the exhaust “back pressure” which is affecting the oxygen sensor and the sensor is making an adjustment for this change in back pressure which is causing the engine to run “rich” or burn too much fuel.

I have never removed a catalytic converter and replaced it with a standard muffler, so that is probably a big NO NO, and with out the converter the oxygen sensor does not know how to control the fuel mixture.

I would replace the converter with the same type of converter and leave the system like it was when you bought it, and like it was designed to run with.


Austin Davis

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."
  • Austin Davis

    Hi there, this is a gasoline version correct? If so, start with tune up related items…spark plugs, plug wires, air filter, distributor cap, rotor, fuel filter, ignition timing. Other than that, make sure you are using the proper engine oil weight, the tire pressure is proper and there are no engine warning lights coming on the dash.

    You did not mention anything about it running bad, so I am assuming there are no engine running problems or an exhaust restriction like the other guy had.

    Hope that helps.

  • MR T

    Hello Austin,thans for this oppotunity.I have a 200 v-boot benz and currently been having fuel consumption problem.what do you think could be the problem and the solution.Thanks