You mean the Hall Sensor?

At idle it changes nothing,
but if your driving, you feel a litle less power and a higher fuel consumption.

Gude Mario Audi 100 CD Autom. Bj.83 Audi 200 20v Bj.89 Audi 5000 Bj.85 Audi V8 3,6 Autom. Bj.88