Certain Channels Freezing

[Kitmanik]

We are having trouble with certain HD channels freezing up.  The issue ranges from no video when changing the channel and sound going in and out to an issue when the channel is recorded for DVR use there are lines through the video as it skips and sound issues.  This only happens on the HD version, Standard version of that channel are fine.  2 channels as an example are Free Form and AMC. 

I have rebooted the router and STB as directed by online support and ran the troubleshooter and it found no issues.  Anyone have any suggestions or having similar issues?

[CRobGauth]

If you have more than one stb, does it happen on all?

check coax connection tightness starting at ont through all splitters to stb