I've listened to about 5-6 other 5th gens and they all had the 'knock/rattle/diesel noise' between 1500-2k rpms. Mine is no exception. I started a similar thread a while back after a mechanic wanted me to believe I had a bad engine bearing. After hearing the other cars do it, and several owners of 5th gens on here reported having it too, I disregarded it as normal engine noise for the F22.