Odd Gmail/IMAP behavior

[Nagual]

For a while it worked fine--I did some adjustments to speed up IMAP Gmail in P-Outlook. But for about a day now, it wouldn't download any messages when I hit send/receive manually, even in an area with a strong signal. As soon as the screen went dark when it was waiting, it would stop trying. Only when I plugged it the device to charge, it took a LONG time to get the headers but finally did. It's as if the power setting somehow tell it to stop after a certain timeout, which is annoying.

Is this a Gmail-specific problem or is there something else I can adjust to help this improve?