UPDATE!!! Earlier in this discussion, I posted that I was experiencing iPhone 7 bluetooth connectivity issues with Ford SYNC. Specifically, my iPhone 7 (Model A1778, Intel chipset) would not maintain bluetooth connectivity with SYNC when on a cellular call. It would repeatedly drop and re-establish the bluetooth connection. It would not drop the call, but simply lose the bluetooth connection with the vehicle. I was able to stream music via bluetooth from my iPhone 7 without any issues. The problem only occurred when on a call. I also have an iPhone 6 (Model A1549, Qualcomm chipset) as well. I never had any issues with that phone and SYNC bluetooth connectivity.
I tried all the suggested troubleshooting tips in order to rectify this issue. I was fairly certain that I was wasting my time in doing so, but nevertheless, was willing to give the various steps a chance. Apple support was no help in resolving the matter. They were cordial and apologetic, but were unable to resolve the issue. After doing extensive research on my own, I became familiar with ALL the iPhone 7 models and the different chipsets used in the cellular modems. My iPhone 7, Model A1778, contains the Intel chipset. The phone was purchased from T-Mobile with a T-Mobile SIM. I became convinced that the Intel chipset was causing my bluetooth to lose connectivity when on a call. I decided to purchase another iPhone 7 that contained the Qualcomm chipset. I ordered and received the SIM Free version of the iPhone, Model A1660. The A1660 is compatible with both GSM and CDMA networks. More importantly, the A1660 uses the proven Qualcomm chipset. Since using the A1660, I have not experienced any more bluetooth connectivity issues with Ford SYNC.
It seems quite obvious to me that there is an issue with the Intel chipset and bluetooth connectivity. I doubt there is an isolated hardware issue with my A1778 (Intel chipset). I think it's more likely there are issues with all the intel chipsets. My A1778 is older than 14 days....outside the return for refund window. However, I'll be firmly requesting a full refund from Apple for that phone. I have no doubt that Apple is well aware of this connectivity issue. Perhaps, they are no longer using the Intel chipsets. In any case, if you are having the same issue I was, you might think about testing an A1660 to resolve your bluetooth connectivity problems. Good luck....your mileage may vary.