[HBBates]

I have the same problem and what I now thinking it has to do with is some kind of internet connection /data transfer problem.

I found that sometime after accessing the internet and then closing out the phone still behaves like in up or down loading data.

The way you can tell is, while you can look the running task and see nothing open, you will seen on the top screen bar, where you would have the antenna signal strength bar, you will show data transfer bars.

Just power off and on the phone and you will get the antenna signal strength bar back and the power drain stops