You shouldn't rule out the idle valve just because it has been replaced. Usually the most important code is listed first. Do all the codes come back everey time under same conditions? The first thing to check is all the simple stuff, battery, charging, connections and ground wires.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)