Random upstream power spikes / Internet drops

I'm getting random internet drops due to fluctuating upstream power levels. Most of the time my upstream levels are fine (4 channels between 38-48db). 3-4 times a day at random times they will jump into the upper 50s and the internet times out for a few minutes, then the power levels return to normal. This is very annoying because me and my family due alot of online gaming with party chat on xbox and it cuts me off from everyone and disconnects me from the game. I have tried many different combinations of amps and/or splitters on the main coax line coming into the house to get the signal levels right and its always the same issue with the upstream power so i dont think its a problem on my end. I have a CM1000 modem.