Is your car consuming more fuel than normal?

Every fuel drop counts nowadays because of the non-stop rising of fuel prices. So make sure you won't waste any.

You may want to check your car's oxygen sensor.

Computer-controlled engines in today's engines adjust fueling automatically. This is done through the oxygen (O2) sensor. The O2 sensor reads the exhaust in real time to determine the air-fuel ratio. It then sends the data to the computer, and the computer adjusts the mixture accordingly by controlling the fuel injectors.

Driving with faulty O2 sensor means the computer won't be getting the correct reading of mixture, hence, it won't be able to adjust the air-fuel mixture properly. But if your engine starts and runs, and can stay running, it's drivable. The only problem will be that your vehicle will run sluggishly, or it will stall. The default, limp-home fuel setting of an engine computer unit that received no signal from O2 sensor is an overly rich mixture. this is the safest setting to avoid detonation and burning a valve or piston due to an overly lean mixture. As a result, the engine will be less efficient and consume more fuel because of the overly rich mixture.

The overly rich mixture could clog up the catalytic converter. The extra fuel that's dumped onto the cylinder will have to be burned off in the catalytic converter. The excess fuel will cause the converter to increase its operating temperature, which drastically shortens its life span. The ceramic core of the converter could melt if it reaches a high-enough temperature, which could cause a restriction and eventually clog the exhaust.

It is best to change the faulty O2 sensor one immediately as it is around 10% to 20% the cost of a new catalytic converter.

Driving with a faulty O2 sensor costs you more money on fuel whether during the daily commute or an out of town leisure trip. You may want to change the faulty one immediately.