yes you can inject the cleaner where the air intake boot goes to the manifold, just remove the intake rubber tube where it meets the manifold, and have the engine idling and spray a small quantity in the intake and the engine will bogg down, thats normal. If you do it with the engine off then it will have a build up off cleaner in the intake and will not start until it is dispursed. So it would suggest do it when the engine is idling. I havn't done this on my X5 but I have on many other vehicles and works fine. The other way can clean it is carb cleaner and a tooth brush and scrub away and wipe clean.