[help] kind of boot loop

Hey guys , thanks for your terrabytes of data
i used king root to try to root my xperia m
it is not in warranty
first time , king root failed , and second time , it worked
it installed king user and purify
now , sometimes what happens is :- i am using my phone like usually
and suddenly it restarts .... Then it runs normally , and then restarts ...
In 6 days it restarted 8 times .... I have heard of bootloop problems while rooting , but what is this ?
Its really awkward !
Any help will be welcomed : )