KEVOZS8

i have an Audi S8 1999 recently i am hearing a strange noise coming from the engine from 3000 Rpm until 5500 then all the way to 7000 u dont hear anything except for the beast sound i have went to the dealer they have checked the car for 3 days and then they have told me that the sound is coming from the eninge block cylinder #2 .and they have told me also that this is the first case that they have facing like such a problem .if anyone has an info i will thankfu