iPhone5 Bluetooth - Not Working Properly

My iPhone is not working properly with my bluetooth in my car (2008 Acura). The connection is "hit or miss" - meaning sometimes it works fine; and sometimes it doesn't connect when calling or recieving an incoming call. I've unpaired, the re-established the connection, deleted connectivity to old phone...still an issue.

This problem only started when I got the iPhone5 -- there was never an issue with my old phone (iPhone4).

Any ideas on how to fix?