Internet fluxuates between being good to horrible.

I have the premier package for internet plan from cox down here in New Orleans. After Hurricane Issac I was surprised to find that my internet, t.v. (along with the neighborhood) remained intact after the power came back on. The problem started about a month ago, so well after the hurricane had long past and everything was restored to order. My internet between (11 a.m.-2 p.m.) in the afternoon is perfect. A constant 30 mb download and 3 mb upload. But for the rest of the time it is complete garbage, lucky to get a constant reading from (testmyspeed.net). Most of the time I get errors before the tests are even done, but its about 2 mb download and a 0.12 mb upload. WTF! 

I have a cox technician coming out tomorrow and I've already inspected my lines around the house to look for possible damage to the lines and everything seems in good condition. No bite marks, cuts, bends, kinks or apparent damage, I'm thinking this is a grid problem. Other things I've noticed around the neighborhood is down the street for the last couple of weeks I've seen Cox Technicians on several occasions but never asked what they were here for, could be T.V, problems for all I know, which I have had about 10 times in the last month my t.v. drop out and loose connection and I have to manually restart the cox box.

I haven't had any problems with the modem suddenly resetting or internet going out for long periods of time, just this constant window of 20 or so hours of just horrible internet (not what I paid for most importantly). My Modem is a Cisco brand and fairly new installed by a cox technician 4 months ago, router is only 8 months old as well, both worked together fine. Although I have isolated the router to make sure if it was the problem.  

Things I've done.

1. Call cox to discuss the problem

2. Reset the modem (many times)

3. Restart my computer (many times)

4. Disconnected Router and just have the modem running a straight line into my computer from the modem

5. Inspect the cable lines

6. Looked for similar problems online

7. I also schedule the technician to come out during the time of day where my internet is terrible

8. Made sure no one was freeloading on my internet too (hehe)

Anyone have any ideas on what is causing my internet to be horrible for most of the day? Any insight would be greatly appreciated