Maybe the Foxwell users could chime in. I wouldn't trust it to read all the codes (maybe depends what update you have) and give the proper interpretation. Yes, the throttle pedal has counteracting pots so you would think anything with that would throw a code. You say problem doesn't show up with maf disconnected?

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