I had a problem with my iPhone. It was getting hot to the touch. I then discovered that it was chewing up download data... about 5MB every 15 minutes. This was discovered when AT&T sent me a message that my consumption of my monthly allotment was at 90%.

After many hours of work, I discovered that it was the Exchange server “push”   that was causing it to chew through data. Specifically, it was “push” on the Contacts folder. I ended up extracting my contacts folder to a PST file, and re-importing the file and this seemed to fix the issue of chewing through the Cellular Network Data. [more]

At this point, I realized that I had a problem syncing all my contacts. The contacts would just not all load onto my phone. This was not related to the issue above with Cellular Network Data, but the contacts download would just stop before synchronizing all the contacts. I had noticed this problem forever, but had not researched. It turns out that there were two contacts in my address book that were causing the problem. These contacts have been in my list for years.  After removing these two contacts ( I discovered which ones they were by dividing my list in halves  - binary search- until I isolated the culprits) everything works fine. I have not yet discovered the cause as to why these particular contacts will not sync. I sent one of the contacts to a coworker, and it will not sync with his phone (not an iPhone) either …