Intermittent disconnect

I have read many of the other posts related to intermittent internet disconnects, and am having the same problem.  No warning, no change in gateway status lights...just a dropped connection for 1-5 minutes.  Based on the other posts, changing the equipment within my residence doesn't appear to be the solution.  I would like COX to perform a detailed line test between my house and the street drop, as well as between the street drop and connections further down the network path.  I have a very stable Motorola 6580 gateway modem, that has been functioning flawlessly for several months.  The sudden problems with network connectivity that appear intermittently for 2-3 weeks then stop (over the past 2 years when nothing in the configuration within my house has changed) clearly points to changes at Cox.  This has happened before with Cox, and it appears to be happening again.  I have been a customer of Cox for over 30 years, but if this continues much longer, I will be forced to get a new carrier.  Deliver a quality product or lose a long-time customer.  Thanks.