My old iPhone 3Gs had no problem connecting to my car audio's bluetooth accessory. It would take a moment or two, but with no interaction from me, when I entered my car my iPhone would automatically pair with the receiver. Now, with my iPhone 4S, it doesn't automagically sync. I have to manually bring up Settings>General>Bluetooth and type in a freakin' passcode to make it finally connect. Any clue how I can get back to automatic syncing?