You have probably been stressing over increasing petrol and diesel prices. But have you considered that your stress develops as a result of having a car that is extremely heavy on fuel. Just think about it. If your car engine consumed less litres of diesel or engine, you would probably notice a cut in fuel costs.

On the other hand, cars that are heavy on fuel, does not only cause price concerns but impact the amount of carbon emissions gassing the environment.

The most common cause for a car’s poor fuel economy is due to its oxygen sensors. Oxygen sensors monitor air and fuel, in order for the powertrain control module to increase or decrease fuel, according to the changing operating conditions.

As cars age, the other engine’s oxygen sensor will age. This means that the sensor will respond less to changing operating conditions and create a lean-bias signal, which informs the engine computer to unnecessarily increase fuel consumption.


Here are 10 cars that are extremely heavy on fuel:

  1. The 8-cylinder Bentley Mulsanne EWB containing a 6.8-litre turbocharged engine.
  2. The compact 12-cylinder Rolls-Royce Phantom Coupe containing a 6.7-litre engine.
  3. The 12-cylinder Rolls-Royce Phantom EWB Automatic containing a 6.7-litre engine.
  4. The two-seat 12-cylinder Aventador Roadster LP740-4 consuming a 6.5-litre engine.
  5. The mini-compact 12-cylinder Ferrari GTC4Lusso containing a 6.3-litre engine.
  6. The two-seat 12-cylinder Aston Martin V12 Vantage S containing a 6.0-litre engine.
  7. The sub-compact 12-cylinder Bentley Continental GT Convertible containing a 6.0-litre turbocharged engine.
  8. The sub-compact 8-cylinder Maserati GranTurismo Convertible containing a 4.7-litre engine.
  9. The 6-cylinder Infiniti QX50 AWD station wagon containing a 3.7-litre engine.
  10. The 6-cylinder Nissan Murano FWD station wagon containing a 3.5-litre engine.

If your car is low on litres but seems to be heavy on fuel, these could be your common reasons – apart from inaccurate coolant sensors:

  • Speeding
  • Faulty internal combustion engine
  • Valve leak
  • Aged spark plugs
  • Reduced compression
  • Boot overload
  • Broken engine thermostat
  • Incorrect oil viscosity
  • Dirty air filter
  • Slipping clutch
  • Low tires
  • Faulted brakes
  • Dirty fuel injectors

The best way to deal with your car’s damaged oxygen sensors is to replace it.

If you are not sure whether you car is heavy on fuel or not, you can use a Long Term Fuel Trim (LTFT), to check for the negative result of your rich-running engine. However, 3-litre engines should be the mark if you’re striving for a green fuel economy.

Check out your fuel usage with our Fuel Consumption Calculator!


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