Audi B4 air flow meters

Hello all, This is my first post here, so I should do something wrong please muck quite loudly, ok? My problem: My Audi 80 Avant B4 2.0 E Bj.93 115 PS jumps great even in heavy frost, drives astrein so about 3min. until it gets a little warm. Then it starts to “jump and buck” when giving gas. When it is very warm then the problem has disappeared. 2. Problem: Regardless of temperature or weather, it simply does not bring its full performance. for a 75 HP golf no chance. My workshop has found a mistake with the air quantity meter (read out error memory), and I need a new one. It would cost 350 EUR. Questions to you: Can such a diagnosis be wrong? Is such an LMM cheaper? If so, can you install it yourself? (I’m not a hobbyist) Thank you very much in advance for your help and good driving.