The first thing I’d try is to replace the firmware.
Look at Settings/Info to see what version your hardware is–1.x or 2.x–and then go to this thread:
Follow the manual instructions–this is the last update, so just go to the All Regions links for your versions and install it manually. Don’t install the Updater.
If that doesn’t work, there’s probably a physical problem with the wheel. Try putting some rubbing alcohol (not water) on a Q-tip and cleaning it a bit. If you have a can of compressed air for cleaning computer keyboards, you can also try blowing a little bit of that in there.
