Increasing HD issues with sound and picture, anyone else?

Over the past few months I have been having increasing issues with the sound cutting in/out and the picture flashing. Seems to usually occur in the evenings when trying to watch the major network HD shows. I've changed the box out thinking it was going bad and followed up with the online help with no solution. I've tried calling tech support several times only to be on hold an extremely long time and end up just hanging up. Talking with a few friends most seem to be having the same issues in the NW valley. I sit here now typing being only able to hear half of the show I'm watching...

Anyone else having the same issues??