When an oxygen sensor goes bad the engine may be hard to start, stall, run rough, run too rich, get bad fuel mileage and your check engine light may come on.
When an oxygen or O2 sensor goes bad, it can no longer trigger accurate fuel injection levels, regulate exhaust gas, or ensure efficient fuel combustion.
Consequently, the vehicle may release harmful environmental pollutants or carbon-based compounds and in addition to having subpar engine performance.
Oxygen sensors or O2 sensors help regulate your car engine's air-fuel ratio.
Each explosion in your car's combustion chambers is caused by an ignition of air and fuel.
When the ratio of air and fuel taken into those chambers remains optimal, your car will run and idle just fine.
Driving with a faulty O2 sensor means the computer won't be getting the correct reading of the mixture and 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.
An O2 sensor may go bad due to contamination from substances, such as oil ash and coolant.
Sometimes, O2 sensors simply fail due to time and miles.
In other cases, an O2 sensor may go bad due to contamination from substances, such as oil ash and coolant.
You can drive with a bad oxygen sensor if you can still start your engine and feel little difficulty driving.
But don't leave it alone for over a couple of days, as it might cause safety problems and lead to the malfunction of other parts of your vehicle.
The signs that you need a new oxygen sensor include a rough idle, misfiring spark plugs, lack of power, stalling or a significant increase in fuel consumption.
Once the oxygen sensor stops performing as intended, the vehicle computer detects that and turns on the Check Engine light.
This will usually have a diagnostic trouble code (DTC) of P0138.
Typically, you'd take the vehicle into the shop, where they'd diagnose the issue and replace the oxygen sensor for you.