Galaxy s 4g vibrates randomly

[eagledriver112]

My Samsung S 4g randomly vibrates. Nothing being notified or functions used. It does it when the screen is on and off. I deleted all apps downloaded just before it started. I've soft and hard booted it, and turned off the Haptic Feedback. The same thing happened with my old Motorola droid.
Could it be a malfunctioning battery?

 

[BillboTex]

I am a new oner of this cell phone with T-Mobile, and my phone also vibrates randomly. Could it be G-mail e-mail notifications?

 

[blooper]

my phone use to do this all the time. i think it had to do with apps force closing or having issues in the background. i notice it happens a lot after i look at google maps or browse facebook and then lock my phone.