IVM is the integrated voltage module or integrated supply module. I don't think that is the problem since your symptoms are only present when engine is cold.

Since this problem started directly after the crossover pipe repair I would check my work. There are no coincidences when working on vehicles. You could have a temp sensor connection loose that is screwing up cold start computer input. Check to see if secondary air pump is running when engine is in open loop.

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