How to troubleshoot common engine issues in an Audi?

My Audi seems to be having some engine problems, but I'm not sure what's causing it. It's making strange noises and the performance has decreased. What steps can I take to diagnose and fix these issues?

First, make sure to check your oil and see if it needs to be changed. Low oil levels or dirty oil can cause engine problems. Next, check your spark plugs and wires to see if they need to be replaced. Faulty spark plugs can also affect engine performance. If those are all fine, it could be a problem with your fuel injection system. Have a mechanic take a look at it to determine the exact issue.