Falschluft am Vergaserflansch (Mono- Jetronik) bei einem Audi 80 1,8 S.

Regardless of whether it's the carburetor or another fuel-mixture system, leaking air at the carburetor flange leads to poor engine performance. For small leaks, you can check for leaking air by spraying the intake tract with brake cleaner or starting fluid. This air is drawn in through the leak and causes a change in idle behavior.