it's probably just the limitations of your iPhone. there have been other posts about people having slow reaction time to inputs when using bluetooth on an iPhone. There are many bluetooth protocols that can control different aspects of a phone, iPhone probably just doesn't have certain protocols. It's not just iphone, i for example, can't choose songs with voice function through the bluetooth on the radio, but i can call people through the bluetooth with the voice function. I also can't browse music, but my friend's Nexus can. it just depends on the phone, there's nothing wrong with the car.