I'm having poor "sending" audio quality iPhone4s iOS7 bluetooth Chevy MyLink

My Chevy Mylink (2013 Chevy Traverse) doesn't seem to like working with my iPhone4S iOS7. I can hear others great onthe phone, but the "sending" audio quality to them is barely useable. Anyone encounter this? I've tried the phone reset, etc. as suggested in the guides, user forums, etc. Right now, I have to resort to pairing my phone to my old TomTom GPS to use handsfree. Very annoying, to say the least......