Those T3 timeouts will cause problems. Every T3 timeout represents packet loss that causes the internet to cut out. Check all of your interior connections, remove unnecessary splitters and replace all interior cable with brand new high quality RG6 if possible. If you do all that are are still getting T3 timeouts you need to call for another tech since the first ones probably missed something. There is always a small chance that it's a defective modem but that's a very small chance compared to how often Cox blames the modem.
