I have a Pioneer FH-P8000BT in my car, which worked just fine with my old cheap feature phones and my old iPod touch, but the bluetooth function is unreliable with my iPhone. I can get it to connect and transfer the phone book just fine, I can start a call, answer a call, and siri sometimes understands me. The issue is sustaining a call. The conversation starts to break up, as if I am loosing a signal, but when I change over to using the phone without bluetooth, it's just fine. This happens with and without the USB connection to the stereo. I exchanged the phone and have the same problem. I can't figure out why I can get cheap phones to work just fine, but my iPhone goes nuts when using bluetooth in the car. I tried using an old plantronics earpiece with the phone for comparison. Surprise, that works just fine, and siri understands me even better. I'm stumped and don't buy that it's the stereo because, as I have said, it worked perfectly with crap phones. Any ideas?