"Android System" using 90-100% CPU

Lately I have noticed that "Android System" has been constantly using 90-100% of my CPU, causing lag and battery drain. At first, a reset fixed the problem, but now even that doesn't help, even with a battery pull. I have noticed Android System jumping up my "Battery Usage" list higher than in the past. I cannot for the life of me figure out why Android System is taking up so much of the CPU constantly.

I've tried turning WiFi, GPS, background data, auto-sync, etc. on/off, but to no avail.

Can anyone help me figure out what to do? Is anyone else experiencing the same problem? What could be going wrong?

I'm not rooted and I do not have a task killer. But I do have Watchdog (that's how I noticed the problem), which repeatedly gives me notifications that Android System is detected above the threshold level for the CPU monitor.

 

Yeah, I know about running services, but that isn't helpful. It does not tell me why Android System is using so much CPU constantly. There isn't much running since I just rebooted.

 

Yeah, I though it could be due to some applications at first too, but that wasn't the case (none of the apps in my list appeared to be using the amount of CPU and battery that Android System was). I had done a battery pull and sd card pull when I shut the phone down one of the times I did a reboot. I really wanted to avoid doing a factory reset because I've done a lot to my phone (apps, settings, customization, music, photos, etc.) and didn't want to have to wipe everything and go through setting all that up the way I like it again. I tried having background data and auto-sync both on and off to see if that was making a difference. I gave it plenty of time to calm down after reboot (several minutes, to the point where normally the CPU would calm down to 10-50% under normal use and conditions). I tried toggling WiFi, Bluetooth, and GPS on/off. After tweaking some things and doing another reboot (this time while plugged into a charger, although that probably didn't have anything to do with it), it finally appears to be back to normal (whew! I was freaked out there for a while). It started working right last night and I still have not noticed the problem recurring through all of today. In doing a couple hours of research online, I found that this is a problem several people have experienced with their smartphones (it could be a bug with 2.2, because various phone models have reported issues), and to which no one has a proper explanation or solution (from what I could find, just lots of - "well did you do this, do you have this setting selected, are you using this app, etc."). Oh well, it is back to normal now (at least for now), so I'll keep my fingers crossed that it does not come back again and will be fixed with an update in the future.

 

Thanks for the suggestion. If the problem comes back again I'll try that next time. I am reluctant to download an antivirus app though because they use CPU/memory/battery. This isn't Windows so they aren't really necessary.