Emily_M, let's put on our glasses and find this culprit! There's no way to confirm which application is causing the issue. As a result, you will need to uninstall applications one at a time until the issue is removed. Tap Settings>Tap More>Application Manager>tap the Application>tap Uninstall. Keep us posted.
Follow us on Twitter @VZWSupport
Just spent last hour in the car trying different things. Now it doesn't even work in safe mode. Every time I shut the car off the boxes under profile for call audio and media audio un-check which is why I have to re-connect every time. I've uninstalled every third part app, done a soft reset and keeps doing the same thing. VERY frustrating!!
I did some research and found a site that said to pair the devices using the vehicles voice commands instead of manually. This seems to have worked! No clue why but I'm happy it did the trick.