Why it matters: O2 sensors feed critical data to your ECU, helping maintain the ideal air-fuel ratio for performance, efficiency, and emissions control. Reading the signals: Healthy upstream sensors ...

Let's begin with the basics here: An automotive oxygen sensor is part of the exhaust system and does what its name implies, sensing how much oxygen is in the exhaust gases. And that's important for at ...

QUESTION: I own a 1999 Buick Century. The indicator that shows gear position does not light up, and at night I cannot see what gear I am in. Is this an expensive repair and worth getting fixed? ANSWER ...