You can try rapping on the MAF with your knuckles while the engine is running to see if there is a stumble. (doesn't rule out a bad MAF though) You can also try disconnecting the MAF (key off) and try taking it for a drive. (doesn't mean for sure the problem is the MAF but gives some direction) The throttle pedal pots giving offset or opposing signals is normal. Are you really really sure there are no codes? How old are the spark plugs?

and yep, idle air control might be worth a try.

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