Originally Posted by MichaelKies

Guys, just got my car back, and sure enough they changed out the MECHATRONICS (MECHATRONIX? Ive seen it spelled both ways). Ive had the car for 3 days now and the surging problem is completely gone. Since the tech was able to re-create/witness the surging BMW covered the repair completely under my 100,000 mile extended warranty (and from what Ive read its about a $4000 fix). Like Ive posted before, I also had a friend with the same car and same issue and he ALSO had the Mechatronix changed out and it resolved the problem!
Have the tech RE-CREATE/WITNESS your problem then MENTION that you have read online about the Mechatronix problem. They SHOULD take care of it if youre still under warranty!