Air mass meters?

Hi guys.. For a few days now my Hilde (Ford Fiesta BJ 96) worries me. In the stand with running engine, it sounds very restless, as if the car is always re-regulating until it is drunk from time to time. Speaking of, if i brake strongly or at all brake, the car runs out. Can it be that my air mass meter soon pulls up the hooves or can it be something else? How expensive would that be if I had it done in the workshop? at the moment everything comes at once *kotz* Bergige Grüße aus Tirol Lunatic