I had an intake duct fail on a non-BMW vehicle, a VW, some years ago. Vehicle was 6 months old. It caused a reduced-power mode. Co-incidentally, that part was on national back-order as well. They forecast 2 weeks to get one to me. I tracked down that they were all failing, and VW had frozen all related parts inventory because they were from the same manufacturing lot, so they didn't know which ones were 'safe'. It wasn't strictly speaking a delivery problem, but rather a supplier manufacturing problem. I was several thousand miles from home. I convinced the dealer (in Siena Italy, and working in my very basic Italian) to take one off another vehicle on the lot to get mine running (temporarily), until the new parts were available. They did so. Worth a try.

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue