20 September 2002: If your car has done over 18,000 miles, it could be costing you as much as 15 percent extra fuel consumption unnecessarily.

That’s the suggestion from Bosch, manufacturers of the sensors in the lambda systems that are an essential part of the modern car’s engine management equipment.

The sensor provides information on exhaust gas and helps the management system to ensure the correct petrol and air mixture is maintained in the combustion chambers.

But Bosch, whose sensors are used by almost all manufacturers, advises checks every 18,000 miles because the sensors can be damaged and made innacurate by wear and tear, contaminated or leaded petrol and oil or water in the combustion chamber.

The overall damage to the car’s environmental protections systems can include a deterioration in the performance of the catalytic convertor, leading to more pollution and poor fuel consumption.