TV cutting out/pixelating splitter issue?

So ive been having issues the past week with my cable cutting out or pixelating every 10/30 seconds. I have one line straight into my house with a splitter. One cable goes to my xfinity modem and the other to my cable box. I unplugged the splitter and ran the cable straight into my cable box and the problem instantly went away. No problems for over an hours, so I decided to get a new splitter thinking that was the problem, but as soon as I hooked up the splitter Im right back to the pixelating problem.  Any Ideas whats going on?