While knocking is no longer as widespread a problem thanks to the current state of anti-knock sensor technology, it can be an issue for vehicles with gasoline direct-injection engines.

They all have knock sensors that automatically adjust the timing if you happen to get gasoline that has too low of an octane rating. So it's possible you have a bad knock sensor.

A knock sensor is important to a car's fuel efficiency. Learn more about what a knock sensor is, what it does, where it's located, and how it works.

Q: My 2000 Nissan Pathfinder was diagnosed with a knock sensor problem after a mechanic scanned the OBD2 codes. (The check engine light is on.) It did not pass the annual inspection. The car has ...