jailbroken ipod touch 2g problems?

so i have a jailbroken iPod touch 2g (redsn0w) running 3.1.3 firmware. for the past few months i've had some problems with it randomly turning off when it's in lock mode, and when i go to turn it back on, it is unresponsive, so i have to reboot it by holding down the power button and the home button. when it eventually turns back on (it takes much longer rebooting when this happens than turning it back on when it's normal) the battery life (starting from a full charge) can be anywhere from 50% to 0%. i have re-jailbroken it several times with different jailbreaking programs (blackra1n and spirit) and have even uninstalled winterboard and a few other programs i had gotten from cydia, but it didn't help at all. it happened to me when i was running 3.1.2 also. my friend has a jailbroken ipod touch running 3.1.2, but it doesn't happen to him. i need help!!! i'm running out of ideas...