Is Your Car Guzzling More Fuel Than It Should?

Under-Inflated Tyres

The most common, easiest-to-miss cause — low tyre pressure increases rolling resistance without any obvious symptom beyond the fuel bill itself. Worth checking first, since it's free to fix.

A Clogged Air Filter

Restricts airflow to the engine, forcing a richer fuel mixture to compensate. A cheap, quick fix that's easy to overlook since it doesn't usually come with a warning light.

A Failing Oxygen Sensor

Oxygen sensors help the engine's computer maintain the correct fuel-to-air ratio — a failing one can cause the engine to run richer than necessary, sometimes without triggering an obvious performance issue, just a slow fuel economy decline.

Dragging Brakes

A caliper that isn't fully releasing after braking creates constant, low-level resistance the engine has to work against — often accompanied by a warm wheel or a slight pulling sensation, but sometimes subtle enough to go unnoticed.

Wheel Alignment Issues

Misaligned wheels create additional rolling resistance in a similar way to under-inflated tyres, on top of the more obvious symptom of pulling to one side.

For the specific check on tyre pressure and its fuel impact, see our chapter: Tyre Pressure and Its Impact on Fuel Costs.