I had something bizarre happen yesterday. I was using my D3 as a GPS (as a passenger). Once we knew we'd be on a certain highway for a while, I wanted to save the battery life and put the phone in sleep mode. A couple minutes later, the screen was freaking out in that it would flash the screen on and off at some random interval, roughly once every 2 sec. (showing the GPS map that was there). Then the phone stopped responding altogether. I pressed the power button for 10 sec. at least a few times but it wouldn't turn on or off. None of the other buttons were responsive. I was going to remove the case and battery, but then I heard the phone say "Lost connection" (or something to that effect). About a min. or 2 later, then phone was back on. Very bizarre! It was fine after that, but I didn't put the phone in sleep mode w/ GPS running after that either.