I own a 3Gs and recently upgraded to iOS4. Since my upgrade, the quality of the bluetooth audio when paired with my car stereo is very degraded. The sound is hollow and scratchy. Any similar experiences and/or suggestions to resolve this issue? A few more specifics: I only use the bluetooth audio in my car so I don't know if this issue extends to other connections. The car is a Nissan Versa. This is not a new iPhone4 so this is not related to the iPhone 4 antenna issue. In my case, this is the same phone, same car, same mounting position in my car. The only change is the new OS. UPDATE: Since the original post, I've found a few other reports of degraded bluetooth audio with iOS4 (all MacRumors threads): here, here and here. One of these is also with a Nissan. Others are with iPhone4.