Hi Guys
I had same problem and I wanna share you my experience.
My scenario is a Samsung Galaxy Tab with JellyBean Cyanogem 10.
Basically I followed all tips I have found with google and nothing worked. Factory reset, wipe cache, reinstall ROM, etc. Nothing
So I installed CatLog application and started monitoring log and I found the following:
ANR in system
04-13 12:19:29.740 E/ActivityManager(323): Reason: Executing service com.google.android.backup/.BackupTransportService
Then I got that Google Backup service was blocking system. As I dont use this service just removed(uninstalled it).
The issue was solved.
I am not saying it will be the same issue for all of you, but just an ideia on where to start to identify the problem.
Good luck all of you.