jlc767for over 5 years I've dealt with frequent disconnects from Cox, spanning two separate apartments and a full generation of hardware upgrades and I'm still getting disconnects! I don't know what the issue is, but I'll tell you what it's not: anything on my end.
People like to believe that, but it really could be. It's amazing how much can go wrong with inside wiring. I used to get a T3 timeout every day or so, until I replaced all my jumpers and splitters one weekend. I had no reason to believe they were bad, but I did it anyway. Now I haven't had a T3 timeout in 18 days.
jlc767I've had techs out multiple times checking the cable connection
Not for over a year, and then almost a year prior to that. If your idea of techs coming out multiple times was more like most customers, this could be fixed by now.

jlc767at the wall and they've all said the same thing, "it's fine." But never once was the line at the street checked, or any outdoor lines replaced.
No lines would be replaced at the street because we can see from here that many of your neighbors already have better signal than you, and the drop from the street to the house wouldn't be replaced if the technicians took readings at the point of demarcation where it meets the house and found it within specifications at the time.
jlc767Reading the forums, this seems like a massive problem for Cox
It's really not. That's just confirmation bias. People forget that the complaints they see online are a tiny subset of about 5 million customers.
jlc767I'm not even going to bother calling Cox (again), because they'll just offer to send out another tech to check the wall line.
That is actually what I would like to do, but I'd want them to look for some specific things that previous techs may not have noticed:
Your new modem has a high power adjustment count, which indicates either a problem with the modem itself (which is unlikely with a new modem), with the power supply to the modem, with line amplification at either an amplifier within the home or at the tap outside, or just a general wiring problem.
There's much lower signal-to-noise on the 561.0 MHz downstream than the others. This probably indicates ingress, because that happens to be the same frequency FOX 43 broadcasts on (UHF 29, 560-566 MHz).
If you email us at coxhelp@cox.com, we can set up a service call with a technician who will know to look for these details, and we should be able to straighten this out once and for all.