How do I troubleshoot low engine power on my Audi A4?

I recently noticed that my Audi A4 doesn't have as much power as it used to. What could be causing this and how can I fix it?

The first thing to check is your air filter. If it's dirty or clogged, it can restrict airflow to the engine and decrease its power. A simple fix is to replace the air filter with a new one.

Another possible cause could be a faulty oxygen sensor. This sensor measures the amount of oxygen in the exhaust and helps regulate the air-fuel mixture. If it's not working properly, it could be causing a decrease in engine power. You may need to have it replaced.