Hi all, did you ever found out what was causing this? My N52B30 is very rarely doing the exact same noise on deceleration, only after some spirited drive ... Some time ago I changed vanos check valves, hoping to fix a light chain rattle when temperature were really cold and engine oil wasn't at operating temperature, old valves were stuck and new ones eliminated that bad noise from the chain not being properly tensioned, I wonder if this noise has something to do with it .. 2 years ago, when the engine already made in two / three occasions that sound , when changing valve cover gasket I couldn't see any obvious slack in the chain, it wasn't movable at all, but probably it isn't proof of the chain being healthy ... Any ideas? Did your car started doing this all of a sudden or developed the noise in some time?
Ps. Being N52 port injected and N53 direct injected, doing the exact same sound, I would rule out the fuel system ...
Pps. Sorry to all, german nor english aren't my first language.. .