Phone constant reboot

I wasn't sure if I need to add reply to one of the topic or have similar topics. So I am creating new thread.
Hello,I have wind S3 T999V.
Before, the phone did not reboot constantly. It is just few days ago, the phone is reboot constantly.
There is enough battery and I did not click on power button to turned off the phone.
Sometimes, if I am in browsing or open the app, it sometimes turned itself off. Also, sometimes, when I click the power button, the menu interfaces for turn off, reboot come out several times and go turned off itself instantly. Then when I need to turned on again, it reboots several times stuck in boot menu and the phone is on.
So, what I did is since this is rooted phone, I backup my rom, clear cache/data, and install 4.3 Touchwiz StockMod custom rom with 4.3 modems. At first, I thought the problem has solved. After restore apps and used for few hours, the phone now has same problem again. At this points, I am thinking it may be phone itself has problem.
What steps should I need to try out?

I tried leave my phone with factory reset and no apps for overnight. Also, I am in safe mode for the phone.
Actually, with no apps and factory reset, I think it does randomly shut down as well.
However, as I play with power button, sometimes, the screen does not shut down and turned on twice or sometimes, power options prompt come out.