Hopefully there will be some codes to help pinpoint the problem. Sounds like everything was fine and all of a sudden it isn't? Terminator has asked the key question without a scan, how the engine reacts to peddle pressure both driving and in neutral? I have seen your symptoms when a cat crashed and that happens without any warning. If it started directly after taking on fuel, was it from a 1st. rate name brand source?

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