FT,
I suggest that you unplug everything from the com port except the IntelliFlo.
If the pump's display says "Display not Active", that should mean the com port is ok..
Then, one at a time, add additional connections until you find the bad one.. If there is a bad one..
Since it is intermittent, I would wait a while between each addition.
I would add any remote last. And ScreenLogic, next to last.
Thanks,
Jim R