Data connection shuts off - won't restart

I have an intermittent annoying problem with the Sprint HTC Touch Diamond.  It will randomly turn off the data connection.  When I go to the Comm Manager (Start -> Settings -> Connections tab -> Comm Manager), I can see the Data Connection is off.
I click on the Data Connection and it blinks but does not attempt to start the data connection.
The only way to restart the connection is to push the reset button on the back of the phone.  After the restart I have to go back to the Comm Manager and click on Data Connection but this time it'll start.

This usually occurs when I'm not actually using the phone.   I called sprint tech support but they had no clue. They just told me to reset the phone.

Any idea why?