[AT&T, Rogers, Bell, Telus Samsung Galaxy S III] obfuscated:
Hello! I've been lurking around trying to solve my battery drain issue for two days without success. I have a d2att with severe battery drain, where battery would last for around 2 hrs MAX before shutting down at 40%. This was apparently an issue before (my brother was using it) when it was on stock unrooted 4.3. I installed Carbon 4.4.4 to look for improvements.

Symptoms:

Rapid battery decrease during use

Shutoff at 40% (when rebooting it would show 0%, when charging it will start at 40%)

Constant wake (I believe from the systemupdate wakelock that is unstoppable)

Feels warm during short times of use, cool when standby

Attempts to fix:

Using GSAM to monitor battery drain (just installed Betterbatterystats, will update with that info later)

Installed MyAndroid Tools and Disable service to stop systemupdate and checkin services

Autoruns to stop all systemupdateservice receivers

Dalvik cache wipe to try to fix the 40% shutoff

Privacy guard to turn off keep awake for Google play services and Android system

Privacy guard to turn off location for GNow

Have not done:

Replace battery (just ordered one that's coming in two days)

Clearing batt stats, as apparently that doesn't help

Factory reset, as it's a pain to setup again (Should this be next?)

Greenify

Xposed

I am just generally confused at this point at whether systemupdate service is turned on or off, or how to solve that, or if that is even the main problem, and what my next steps should be. I'm not an expert and can only understand half of what's going on, so any advice is greatly appreciated!

*Update: It seems that the phone is able to go to deep sleep (~50% of the time). When I use it just 5 minutes for texting, the battery can drop 5%. After reading from another thread, I re-enabled systemupdate services from Disable Services/My Android tools to see if that would solve the problem, and it looks like it is not hogging wakelock anymore; however it does revert on boot, similar to this: forum.cyanogenmod(.)org/topic/96459-systemupdateservice-wakelock-on-cm11-m7-massive-battery-drain/

Update 2: I flashed Liquidsmooth 3.1 stable instead. This time I used autoruns manager and wakelock blocker (included in liquidsmooth settings) to disable the services, but systemupdate service still manages to run, so I have to disable the block to somehow make it stop with every boot. Once that is fixed, deep sleep functions normally, but now the new problem is that Chrome browser app seems to be stuck in an AudioMix wakelock. I uninstalled Chrome updates and this seems to have fixed that issue, however battery drain is still severe (5%/2min) during active phone use. No application stands out in constant wakelock anymore, so I'm suspecting it may be the battery itself? I will switch to a new battery tomorrow to verify.

Update 3: Well since no one bothered to help, I will just post this for future reference as a log, since I solved the last part by the battery switch to an Anker battery. The phone still gets hot, and I still have to manually deactivate systemupdate service on every reboot, but now it runs for "normal" times 5-6hrs (heavy use).