This is my third reply to this thread FYI.
For me, this has nothing to do with data plans or not. My phone when set up to talk to my Exchange server using push (not IMAP), will continually use the radio or network interface to attempt to connect to the exchange server -- every second --, forever. My exchange server logs confirm this.
The poor battery life and heat is caused by both the CPU running constantly and the radios (wifi, edge, 3g) being in use constantly. This jibes with others who have reported hearing interference in nearby speakers "constantly" (which means the radio is transmitting "constantly").
As a point of interest, my original complaint was on my 1st generation iPhone. I received my new 3GS yesterday, restored a backup from iTunes (as I was prompted to do) and sure enough, my new phone started hitting the Exchange server every second, the phone started getting hot, and in 15 minutes, the battery was down about 25%. So its not the phone -- dont let anyone tell you it is ("genius" or not).
This should be really easy to diagnose since its happening to a lot of people using push and or exchange and it is
not intermittent.
I "fix" mine by disabling the Exchange email account on my phone and rebooting it. (that is the only other "push" email account I have). AP News ap and its "push" has nothing to do with my issue. Turning off the exchange push email account does...
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