500 plan speeds drop to 30mbps

You are inaccurate. I have an RG6 cable from the box to my house that was installed in 1998. The ONLY reason it would need to be replaced is if water got inside. As long as your home connector has the proper watertight insulation on it, you should be good. ALL the center wire carries is an RF signal, much like a radio antenna. 

When mine needed to be replaced, it took Miss Utility 40 days to come out and mark the ground, (Important because out electric grid is underground here), and within the week, Cox was out and replacing the run. Spreading misinformation only makes you look sad. 

Ehh, 10 years is about right for coax replacement, atleast for any cable line ran along the outside of the house exposed to the sun and elements. The line will dryrot and crack and you'll start to notice poor service specially when/after it rains and water soaks into the line, until it dries out. But yea, 10-15 years sounds about right with us starting to see service issues every time it rains starting about a month ago and we had ours re-ran about 10-12 years back. 

I'm sorry to hear you've been having this experience. We hope the tech appointment goes well. If you have any concerns after that is completed, please feel free to email us at cox.help@cox.com. Thank you. 

So the second tech was out and identified a bad tap outside, said inhouse techs will need to replace it should take 3 days, its been week and half and no one came. Since the tech left cox app now shows network impairment event and i dont know if its related to that issue

 Hi, there. I am sorry no one has made contact with you.  Please email my team at cox.help@cox.com so we can obtain account details and review further.

Thank you.

Tech came and replaced the phone/cable box on the side of my house and replaced some old coax connections. No change - 500 when the modem resets then back down to 30 after a minute or so. He went up the pole and said signal strength there is bad and outside plant dept needs to check it out. 

Once they come out I'll give you another update.

Hello friarfaithful,
We can help investigate this on your behalf. When you have a moment, would you send us an email to Cox.Help@cox.com with your name, complete address, and the URL to this forum comment? We can check into the status of this if you haven't heard back since this last visit was completed.

Again, Try using a different ethernet cable, and reboot your laptop into "Safe mode with networking", and run the test. If you are seeing the same issue, then it's indeed something with Cox. If the speeds increase dramatically, and stay that way, you have a piece of software on the laptop running in the background that is slowing it down. 

It’s not that. Whole network drops to 30. Wi-Fi, LAN, different laptops, swapped ether. Tech discovered problems at the pole. 

Call in to tech support, and request escalation to CAG. They are far more knowledgeable and will be able to either assist, or get the right person on the fix for you.