Weird Vibration Issue 3G

[ninicp]

I have an iPhone 3G running iOS 4.2.1, not jailbroken. Whenever I press the top left corner of the face of the phone it vibrates. I have to put a little bit of pressure on it, but not too much. Is this a hardware or software issue? Any idea if this issue is fixable or if I just need to wait for iPhone 5? It hasn't always done this, but I just discovered I could make it vibrate whenever I wanted by pushing with slight pressure. Also, this makes the sound/no sound icon appear on screen. No other odd behavior that I have noticed other than a general slowness of iOS 4 on iPhone 3G.

[A3gOwner]

I'd say either the switch is bad or the ribbon cable that connects to it is bad. Both are an easy fix tho.

[bmwraw8482]

i used to have 2 iphone 3g's and they both ended up doing the same thing after about 11 months so luckily i was able to take them in for a replacement, which i sold for the same price as my upgrade to and iphone 4.
hope you're still under warranty cuz that was a really annoying issue to me