Stock 4.3 upgrade killed voice navigation over bluetooth ?!
I used my and my GFs GS4 4.2.2 for BT in car navigation (google maps) happily for almost a year. Then 4.3 came along, and although everything is mostly fine and dandy BT voice navigation refuses to work. BT music/calls work just fine, but with voice navigation it looks like there is a delay of 3-4 seconds before voice over BT 'kicks in' so it clips almost all of the voice navigation and once in a while you hear last couple of words if they take longer to say than 3 seconds.
I tried switching to samsung text to speech, no luck. Looks like this is due to Samsung upgrading the BT stack to support low power BT.
My GS4 is with Fido, and GF's is Rogers (I think they are all the same anyways).