Sync also churns in iTunes when it hits contacts. Software on phone slow. Feeder with spiral. Freezes. When are they going to fix?
Sounds to me like you should wipe the iPhone, make sure you have the current version of iTunes and maybe reinstall it, and restore the unit and try to resync...
and make sure your usb dock connector isn't bad...
and there has to be more detail to this problem you aren't communicating to us... but based on what you've said.. thats what i'd do
