Yes-- our home in ternet too!! it crashed yesterday and my wife finally got it back running only to have it crash this afternoon. we now cannot get a live human being on the phine to fix it!!! I THOUGHT COMCAST HAD A CUSTOMER GUARANTEE 24/7 LIVE SERVICE.
Your power levels are out of spec. Are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured ? If not, perhaps a tech visit is in order to investigate and correct.