You just got the X5 right, how was the service record on the car?if I where You I would use a good oil [Castrol titanium ] it really cleans the whole system , also use chevron fuel injector clear better know as techron, and use it every 4k miles.
So basically baby Your baby for a bit and helpful it will clean it self out .
It did for me and all is well now........... the best way to clean the engine is to do the oil change and add the techron and some good fuel[93oct] and go for a long ride.....

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2006 4.8IS
65K MILES
PURCHASED 7/13