Since the weather has changed I've noticed an Idle surge (600 to 900 rpms) when standing. The Tach needle just bounces and the idle goes from 600/700 to 900 rpms. It doesn't seem to occur with the air on.
Anyone else have this problem? I did a few searches but all I could find was VIII and IX not on the X.

 

Are you using a Cobb Accessport? There were issues with older maps causing a surging idle...but that has been fixed with the most recent ones.