How do I troubleshoot a faulty engine on my Audi 80?

My Audi 80's engine is not running smoothly and makes strange noises. What steps can I take to diagnose and fix the issue?

First, check the fuel system for any clogs or leaks. This could be causing the strange noises and poor performance. Next, inspect the spark plugs and wires for any wear or damage. If necessary, replace them. Consider also checking the air filter, as a dirty filter can also affect engine performance. If you're still experiencing issues, it may be best to take your Audi to a mechanic for further diagnosis and repair.