My experience with MAF going bad was that it first caused a rough idle, it gave you warning. That said, to test the MAF, unplug the connection. If the condition improves or disappears the MAF is the culprit. I can't think of air blockage that would come on that fast, or spark. I suppose fuel could but not likely in your case unless you were sucking the tank dry. The long idle time has me leaning toward a cat or something in the emission system but I would think it would light up the dash with warning.

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X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas