I would first suspect signal issues. Easiest way is to check the digital signal strength on channels you're having trouble with. Go to Settings & Messages > Settings > Channels > Signal Strength - Cable. Once into Strength Meter is on screen, tune to channels where you're seeing the most pixelation. In my experience, anything channel with 50% or below will have noticable pixelation. Check other stations as you want. If you're seeing low signal, check/tighten the connection to your Tivo. If you still have trouble, try a new coax cable from the wall to the Tivo. You could then also move the Tivo to another room and check signal strengths from a different Coax outlet. If, after all this, the channels are still crappy and signal strength is low, call Time Warner and get a tech out to check the outside wiring, as something is likely damaged.