Hi, I posted about this same issue many months ago. I wanted to find out if there was a way to change it because I found it very annoying. Unfortunately, I have some bad news for you. After trying to find an answer for a very long time, testing countless things, and sending in my phone in to have the issue inspected, there simply isn't a way to change it. Actually, there is ONE thing you can do that will stop it from vibrating completely. Under your messaging settings there is an option called "Also vibrate when notified". Turning this off will stop it from vibrating when it rings (with sound turned on). However, if you switch your sound settings to vibrate, then it will be silent and do nothing when you get a call, message, etc. You would have to go back to the message settings and turn that option on/off every time you change your sound settings. To me, that's just too much of a hassle every time I change to vibrate and back, so I just try to ignore it even though it bugs me to no end.