What are some common troubleshooting techniques for fixing a malfunctioning Audi A1 engine?

I recently bought a used Audi A1 and have noticed some issues with the engine. What are some common problems that occur and how can they be resolved?

One common issue with Audi A1 engines is a faulty oxygen sensor. If your engine light is on, this could be the cause. It's important to get it checked and replaced by a professional mechanic, as a malfunctioning oxygen sensor can significantly impact your car's fuel efficiency and performance.