I have had an iPhone 4 and a car adapter for my car which has a dock connector on one end, and on the other a 3.5mm headphone plug, along with a cigarette lighter charger. I use it to charge my iPhone and play audio through my car's stereo with only having to connect one thing. It has worked fantastic. I pretty much only listen to Pandora in my car when I drive now instead of the radio. I got my iPhone 4S on Friday, and have noticed that there is a rather frequent popping noise coming out of my car speakers when connected. I still have my iPhone 4 so I connected that, just in case something has happened to the adapter, and it was fine, played with no popping noise. If I use the headphone jack on my iPhone 4S, there is also no popping. Just through the dock connector audio. Has anyone else here experienced this? I thought I was safe assuming all iPhone 4 accessories would play nicely with the 4S, but perhaps there's some strange incompatibility here. Thanks.