NOPE!! Still driving me nuts. Pulled plenum off this weekend and pulled ICV (not trivial on S38 engine)- it was sparkling clean but cleaned it anyway. Set base idle (another S38 adjustment). Yanked cover off of AFM and played with it a bit. Nothing has helped. Latest thoughts are bad ECU, possible injectors issue but not likely, maybe a bad/intermittent coil?? WHo knows, but I'm not giving up!