Mixture adaptation/ skim limit below

Hello A2 driver, since 1 month I am now also the owner of an A 2 – 6/01, 1, 4, 60000 km run private purchase booklet and super maintained, but no warranty;( I love this car, but unfortunately he now already does many problems indicator light motor electronics – started it with a loose hose – well can happen – – then 1 week later same problem. Lambdasonde replaced – Well, well! – 3 days later it lights up again Now the error message at Audi announces the following: B ank 1 mixture adaptation range 1 lean limit below P 1151-17559- okay, Audi deletes the error makes a visual inspection and finds everything in order. I still notice a power loss and a consumption of up to 16 liters in the display when picking up. Furthermore, it doesn’t drive as quietly as it did before. Although nothing shines anymore, but that doesn’t help me either. I read a lot of things in the forum about this, but nothing concrete was possible. In addition to: Speed sensor replaced and error fixed, I wanted to ask if others have already had this experience and there were other reasons. Above all, what you did to fix the error would be helpful.Experiences and insights Thank you so much Please do not visit other friendly workshops because I already plan to do so.