Can a Bad Oxygen Sensor Reduce My Car’s Fuel Economy?

A bad oxygen (O2) sensor will directly affect your vehicle’s fuel economy. In fact, you will see a significant reduction in your gas mileage with a malfunctioning O2 sensor. CAR FIX recommends that you have the failing oxygen sensor replaced as soon as possible. Otherwise, you will not only see a reduction in your fuel economy but your vehicle will also suffer from the following things.

Black Exhaust

A failing oxygen sensor can create a fuel-rich condition in the combustion chamber and you will end up with black exhaust. The exhaust flowing out of the tailpipe is an indication that your engine is burning too much gasoline or diesel fuel. You will end up with the annoying exhaust until such time as you get the oxygen sensor replaced.

Check Engine Light

Your check engine light will also come on because the oxygen sensor will send an error code to the engine control module. This usually happens at the first O2 sensor malfunction. The check engine light is a crucial tool for your engine’s health. If it comes on, you know there is something wrong with your vehicle’s engine.

Engine Trouble

Aside from the dashboard warning, you may also have engine trouble. For example, assume for a moment that the malfunctioning O2 sensor has caused an air-rich condition in the combustion chamber. When this happens, your acceleration will lag and your engine will stutter and struggle to run. When there is too much fuel in the engine, your vehicle will surge, which means it picks up speed in spurts, and may even flood and die. In severe cases, you may not be able to get your engine started.

High Emissions

A failing oxygen sensor will also cause your vehicle to fail the emissions test because you may end up with excess carbon in your exhaust. This happens when there is too much fuel in the engine. Consequently, you will not pass an emissions test if your check engine light is on, as well. The sensor must be replaced so the check engine light turns off in order for your car to pass.

Rotten Egg Smell

Finally, if you smell rotten eggs coming from your engine or in the exhaust, your catalytic converter is going bad. This can be caused by a malfunctioning O2 sensor. When there is too much fuel in the engine, the catalytic converter can get clogged easily.

CAR FIX has three auto service shops in Tennessee: Oak Ridge, Crossville, and Cookeville. Call the shop closest to you if you think you have a bad O2 sensor.

Photo by Bitdlkportfolio from Getty Images via Canva Pro

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