Intermittent connection problems

Hi. I am attempting to troubleshoot some intermittent connection issues I've had for several months on my SB6121, I have 50 mbps service and a few times a week my connection would drop out completely in between periods of extremely slow service, measured ~2mbps on www.speedtest.net. This will persist for a minute or two and then my speed will boost back up to the expected 50 mbps. The connection issues usually repeat every 5 minutes or so for up to an hour and then everything will go back to normal. I got a lot of error messages in the modem log indicating dropped connections when this owuld happen.

This issue has gone on for several months now and we've had a technician out twice trying to adjust the signal strength. I believe one time the technician replaced an amp or a splitter in the outside box, but that didn't really make a difference. Last week, looking at the signal on the modem I noticed that the downstream power level was at +12 dBmV so I installed an additional -7 db splitter which causes my downstream power to read 2-3 dBmV. My signal to noise ratio stays consistent at 36-37 dB and my upstream power is 42-44 dBmV. I'm bonded on 4 channels. After installing the second splitter, my speed will drop as measured on www.speedtest.net down as low as 2 mbps but the modem no longer is dropping the connection as before. The pattern of the behavior pretty much remains the same. I am no longer getting any error messages in the log.

I am on firmware version SB_KOMODO-1.0.6.14-SCM01-NOSH on a motorola SB6121. I've called on the phone 4 times now to complain but after two technician visits I don't have much faith in the tech support people on the phone. Usually they just tell me to power cycle the equipment and make sure it's plugged in correctly.

Anyone have any idea what might be causing the issues and what I could do to fix them?