Yes, I saw you ordered a new pump. Sure hope that fixes everything.

Yes, fluctuating current would result in fluctuating fuel pump performance.

That's a long shot but it would mean tracking back to the power source looking for a frayed wire or connection that is robbing current.

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