Have a 2012 x5m with Renntech 93 octane tune, K&N air filer, regular oil changes, now at 63000 miles.

Beginning to notice an engine knocking, tinkering type noise at high rpms, usually between shifts in excess of 100mph.

Also noting an increased oil consumption, no smoke and no leaks though... If racing or heavy acceleration above 115mph, it will throw a code and enter 'engine malfunction reduced power' mode. happens more with regular octane than 93 octane

Dealer codes showed a cracked #3 spark plug (replaced all and still have problem) and low turbo boost pressure, may have a vacuum leak causing predetonation, or may have oil detonating in the combustion chamber...probbbably not a good thing. any one have any experience with this or can offer any input?