Whats with the D@mn flicker?!!?

[STARSCREAM]

I have an Insignia Plasma and have Cox digital cable. Anyway, on some channels but not all of them there sometimes is a constant white flicker that like outlines people bodies and some objects. Wierd things is that on channels like TNT alot of their movies do it but some don't so I don't think its the tv causing it as some channels don't exhibit it and some only do it on certain shows. Anybody got any clue whats going on? It's really distracting to the point that we can't watch any show that exhibits this flicker.
I'm thinking maybe it's the cable box, but then why wouldn't it do it on all shows. Also TNT here has a constant white snow line that goes down the right side of the screen on the far right. Maybe our cable sucks?