As mentioned in the other thread it will take a lot of troubleshooting to hopefully find the core cause. If you want to check the coils you can swap 1-2 and see if the error moves. Codes and diagnostics can be misleading but depending on your capability $130 may be a value. Does the mechanic do a lot of work on BMWs?

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