some of the tips from the Sync My Ride site
http://www.syncmyride.com/Own/Modules/SupportContent/UsingSyncTips.aspx#phone
Turn OFF the Auto Phonebook Download feature
Try turning OFF the Auto Phonebook Download feature on SYNC. If this feature is ON, each time you connect your mobile phone with SYNC, the system searches for updates. Turning this feature OFF can help stabilize the connection with SYNC. You can choose to manually update your phonebook with SYNC through the Phone Menu.
Check Security and Auto Accept Settings
Your mobile phone may have Security Settings or an Auto Accept function that may interfere with pairing and connecting your mobile phone with SYNC. Check your mobile phone instructions to be sure the settings are not disabling your mobile phone's connection to SYNC.
Increase the volume
If the volume on SYNC is low when you are using your mobile phone, try turning up the volume on your mobile phone—while it is connected to SYNC. Many mobile phones have a dedicated volume control for Bluetooth-hands-free devices, which will also control the volume when it is connected to SYNC.
Remove special ringtones and pictures
If you have problems calling or receiving calls from one or a few contacts, it may be due to a ringtone or picture that is associated with the contact. If this is the case, follow your mobile phone instructions for removing an associated ringtone or picture with that contact. Then try downloading your phonebook to SYNC, again.
Check for missing contacts
If SYNC confirms your Phonebook Download is Complete, but it is empty or missing contacts, it could be the phonebook contacts are stored on the mobile phone’s SIM card. Follow your phone manual’s directions to move them from the SIM card to the phone's internal memory. Once they are moved, try re-downloading your Phonebook to SYNC.
http://www.syncmyride.com/Own/Modules/SupportContent/UsingSyncTips.aspx#phone
Turn OFF the Auto Phonebook Download feature
Try turning OFF the Auto Phonebook Download feature on SYNC. If this feature is ON, each time you connect your mobile phone with SYNC, the system searches for updates. Turning this feature OFF can help stabilize the connection with SYNC. You can choose to manually update your phonebook with SYNC through the Phone Menu.
Check Security and Auto Accept Settings
Your mobile phone may have Security Settings or an Auto Accept function that may interfere with pairing and connecting your mobile phone with SYNC. Check your mobile phone instructions to be sure the settings are not disabling your mobile phone's connection to SYNC.
Increase the volume
If the volume on SYNC is low when you are using your mobile phone, try turning up the volume on your mobile phone—while it is connected to SYNC. Many mobile phones have a dedicated volume control for Bluetooth-hands-free devices, which will also control the volume when it is connected to SYNC.
Remove special ringtones and pictures
If you have problems calling or receiving calls from one or a few contacts, it may be due to a ringtone or picture that is associated with the contact. If this is the case, follow your mobile phone instructions for removing an associated ringtone or picture with that contact. Then try downloading your phonebook to SYNC, again.
Check for missing contacts
If SYNC confirms your Phonebook Download is Complete, but it is empty or missing contacts, it could be the phonebook contacts are stored on the mobile phone’s SIM card. Follow your phone manual’s directions to move them from the SIM card to the phone's internal memory. Once they are moved, try re-downloading your Phonebook to SYNC.
