1st off my phone didn't sleep, even if the screen was locked. it also would not auto-lock unless it was plugged in to my computer.
you can check to see if this is happening by a simple look at your usage.. (mine was at 8 hours and 51 minutes when i woke up after it was fully charged the night before)
i thought it may be the alarm, so i ran a test and nope.
the other problem was that mail crashed every time i opened it. it would update and download the messages, but by the time it was complete it crashed.
simple solve.
ssh into your phone through terminal.
ssh root@your ip address, put in your password, then
chmod 777 /var/mobile/Library/Mail
chown mobile /var/mobile/Library/Cookies/
chown mobile/var/mobile/Library/Cookies/Cookies.plist
on the cookies plist i got an error, but low and behold it fixed both problems.
i was expecting the mail problem to be resolved but it also fixed the sleep problem!