Just started doing it recently, whenever I plug my USB or receive messages, it gets long vibrate (On vibrate mode). However it does not have the long vibrate anymore, it barely turns the motor inside. You can feel motor spinning like 1/2 turn or so, barely can feel it. I called my phone with vibrate mode to see if motor is bad. At first rang, it vibrated like I mention above, barely turn. Then rest were long normal vibrate. What seems to be the problem in this case? Any ideas? Edit: Phone is stock. Factory reset the phone, because vibrate mode did not worked at all later. After factory reset, vibrate worked again, but still having same problem above.