Spikey comcast connection

Ok so I have Comcast with the 8mg tier. For close to 2 years now I have had connection problems at night. For a long time I thought it was my computer but as I changed stuff out and did alot of research I seen that it was my connection. Comcast has been to my house alot and changed the modem twice, all the cables from the house to the "box", and even the tap. They are clueless. The issue is anywhere form 11am to 3pm I will start getting spikes in my connection. When it starts up, ping test will avg 5 normal pings and then 1-3 spikes past apx 150 ping(normal being 40-50 range when pinging yahoo for example). Once it really gets going avg pings are 200+ with occasional drops to low pings. I also get apx 2-6% packet loss on avg. when the connection is bad. This goes on until 12am-2am and then my ping test level out. Also when I say my ping test goes up, it doesn't stay at a consistent number, it always is changing(spikey) making internet gaming absolutely unable to play. Any ideas would be greatly appreciated.