Audi 80 16V does not start, dies in wet weather

My girlfriend drives an Audi 80 16V. Now the problem is that he usually doesn’t jump on wet roads and sometimes he dies even while driving. The problem really only appears on wet roads, nothing is missing in the case of dry roads. So, he can usually start after the 2nd or 3rd time really, then you can also drive, but then he spins. He spins from 900 turns – what my girlfriend as n Or times – suddenly up to 1500, it doesn’t pick up gas and sometimes dies even completely under driving. Ignition coil, idle controller, ignition plug, ignition cable, Lambdasonne… everything new, so it can’t be. I know, by remote diagnosis it’s always bad, but since all the workshops here are baffled, I thought, I just ask, maybe one of you drives the same model and knows what it might be. For help we would be grateful. Greeting, Tanja