HDMI Issues on some channels

I recently purchased a 42" 600U with Cox Cable HD. First off - I love it. Secondly, however, upon switching from component cables to HDMI I have run into problems. Initially I thought they arose from having loose connections. Upon exploring some other HD channels, however, I found that I got great picture and sound on some. Basically on some of the networks I get poor picture and sound quality (cutting in and out, etc) but then others, MTV for example, I get INCREDIBLE picture and sound.


Its seems that this problem only arises when using the HDMI input - when I switch to component its fine. Again - this is only on some channels when using HDMI.


Before I run wiring in the wall I really want to get to the bottom of this. I'd rather run two HDMI cables than a truckload of components.


Thanks!

Billy (In Dubai for the Hometech show!)