How to troubleshoot a failing engine in the Audi 80?

My Audi 80's engine is starting to fail and I'm not sure how to fix it. It keeps stalling and making strange noises. Can someone please guide me on how to properly troubleshoot and address this issue?

First, check your engine's oil level and make sure it's not too low. Low oil can cause problems with your engine's performance. Additionally, inspect your spark plugs to see if they need to be replaced. If they are covered in black carbon deposits, it's a sign that they need to be changed. You could also check the air filter and replace it if it's clogged. If all else fails, it's best to take your car to a qualified mechanic for a thorough inspection.