Posted on 12/19/2025
An oxygen sensor plays a big role in how your engine runs and how much fuel you burn. When it starts to fail, the car usually does not quit right away. Instead, you get a handful of clues that something in the fuel control system is off. Catching those signs early can save you gas money, protect the catalytic converter, and keep you from chasing repeated check engine lights. What Your Oxygen Sensor Does for the Engine The oxygen sensor sits in the exhaust and measures how much oxygen is left after combustion. The engine computer uses that signal to fine-tune how much fuel it injects, constantly making tiny adjustments to keep the mixture in the sweet spot. When the sensor is healthy, the system can react quickly to changes in load, temperature, and driving conditions. If the sensor gets slow or inaccurate, the computer starts working with bad information. The mixture may run richer or leaner than it should, and that shows up as poor fuel economy, lazy throttle respo ... read more