Even though there has been a seemingly increase of people complaining of intermittent connectivity, I haven't heard of any problem that would effect Cox on a national level. Maybe something related to changes made to N+0 or mid split? What state/area are you in for trending reasons?
What model modem do you have and can you post the signal levels from 192.168.100.1? It would help to see them when the service is good and when the service is bad to compare. Also, look at the logs from around the time of lost service. Don't post the logs unless you edit out the HFC MAC address for privacy reasons. What you are looking for is critical items in the logs like T3/T4 time out errors. Last, how does the coax get from the street to the room the modem is in? Any splitters/amp/filter? Is it a house or apartment?