I've been having the same issue ever since I got my iPhone 4S. Previously had my Blackberry connected to BT on my 2012 Impreza Sport Premium and it worked fine. Switched to iPhone and now I have to manually connect each time I get in. Once it connects everything works fine. I've deleted and reset it up several times, but haven't tried the voice command setup yet. I'll give that a shot. Seems pretty obvious that it's an iPhone issue, since my Blackberry worked flawlessly with it.