I have had the same problems for sometime now. The sync would just keep running which would run down the battery quickly. I have had this LTE 4g since its launch. I would delete the account but it would not let me reestablish for about a day or two. So now when my exchange email acts up I just go to the settings in that email, click on download amount which I have it set on "all" , & change it to three days. Wait about 10 seconds then switch it back to all. That usually solves the problem for a short time. Also try a hard reset for your phone. I have to do this about twice a day now. It's been this way for about 6-8 months now. I think Sprint is either having problems with syncs or its the software in the phone.
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