Since you already had technician visits and the problem still occurs, I'm going to escalate your issue for a Comcast Employee to assist further and keep an eye on things.
Since that technician noticed corrosion on those outside lines, that technician should have been the person to submit the ticket to have that line coming towards your pole replaced.
Your T3 errors would correlate with the poor upstream while T4 is typically for downstream errors
Hey there, jbjbjbjbjb, thank you for taking the time to reach out to us here on the forums. I would love to have the opportunity to review this further so that we can get the internet back up and running to its fullest potential! It sounds like there are some issues in the area, but I'd like to check the account to be certain. Please send me a PM with your first and last name to review this further together. Thank you!
To send me a Private Message, please click my name “ComcastAlly” and click “Send a message.”