i was having this problem with Pandora and eventually gave up and uninstalled the app. Recently I installed Spotify on my iPhone 6 and now whenever I plug my iPhone into my car the iPhone automatically runs Spotify instead of whatever was playing on the iPod. I have searched on this problem and it appears there is no real solution? Proposed workaround of using Bluetooth is not acceptable to me, audio sounds noticeably better with the USB connection and has the advantage of charging my phone. It's a bit mind boggling that Apple or app developers don't have a setting that controls this behavior. Anyone have any insight?