How to troubleshoot engine idling issues in the Audi 80?

I have been experiencing some idling problems with my Audi 80. The engine tends to rev up and down randomly and sometimes stalls while idling. What are some possible reasons for this and how can I fix it?

First, check for any vacuum leaks in the engine system. These can often cause idling issues. Then, make sure your air filter is clean and not clogged. A dirty air filter can affect the engine's air flow and lead to idling problems. If both of these are fine, it could be an issue with the idle control valve or throttle body. It's best to take it to a mechanic for further diagnosis and repair.

Another common cause of idling issues in the Audi 80 is a malfunctioning idle air control valve. This valve controls the amount of air entering the engine while idling. If it is dirty or faulty, it can cause the engine to idle too high or too low. I would recommend cleaning or replacing the valve to see if it resolves the issue.