Poor Connection - Possible Bad Signal Levels

I have been having poor, intermittent internet connection for the past week. I have an Arris SB8200 and decided to contact them first. They stated that everything with the modem is good, but the cable signal levels were very poor. I decided to chat with Cox, and got nowhere after about an hour. Should my next step be to get a technician out to the house? I'm just worried that they will tell me the problem is with the modem and that I should have purchased one from Cox. Any help would be appreciated.