Posted on 1/30/2026
Fuel economy usually drops slowly enough that you second-guess yourself. You might blame traffic, weather, or a heavier foot on the gas. Then you fill up again sooner than expected and realize something has changed. One of the most common hidden reasons is a tired oxygen sensor, because it can quietly push the engine to burn more fuel than it needs. An oxygen sensor issue does not always feel like a drivability problem right away. The car can still start, idle, and cruise normally. Meanwhile, the engine computer may be making fuel adjustments based on inaccurate information, and that is where the extra fuel disappears. What An Oxygen Sensor Actually Does Oxygen sensors measure oxygen content in the exhaust stream. The engine computer uses that information to adjust the air-fuel mixture. The goal is to keep the mixture close to ideal, so the engine runs efficiently and the catalytic converter can do its job. Most vehicles have at least two oxygen sensors per bank. O ... read more