Sounds like the coils are not seated and / or a vacuum leak. Could be coils are SWITCHED if that's possible (wrong coil on wrong plug). Check the firing order and pull all coils and reseat to hear / feel a "snap" or "pop" and feel all small hoses for connections / cracks.

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2005 BMW X5 4.8is (E53)
LeMans Blue / Black Leather Interior (Comfort Seats) / All Packages / aFe Stage 2 Cold Air Intake / Software Update / Suncore Industries E53 Air Suspension-To-Coil Springs & Struts Conversion Kit w/Gas Shocks & Warning Message Removal Tool