What is the cause of the unstable idle in my Audi 80?

I have been experiencing a rough and unstable idle in my Audi 80. The car also hesitates and stumbles while accelerating. What could be causing this issue, and how can I fix it?

The most common cause of unstable idle in Audi 80 is a faulty idle control valve. This small component controls the amount of air that enters the engine at idle. I recommend cleaning or replacing the valve to fix the issue.

Your symptoms could also indicate a clogged fuel filter or malfunctioning fuel pump. I suggest checking and replacing these components if needed. Additionally, have the fuel pressure checked to ensure it is within the manufacturer's specifications.