I have a Premier ESPDX, 1 cabinet, that I work on. It has alot of the 8D EVT phones installed
mostly two to a circuit. Lately I've been having
problems with phones starting to motorboat (data
noise). Ive tried repunching the connections, new
line cords but I usually can only fix them by switching to a different port. Some of these phones have been working fine for years and now
are having problems. Am I missing something or is the system just getting old?

I'm assuming the phone punched down directly on the port sounds clear. I have had success by replacing the jumpers with C5e wire and replacing the line cords with C5e as well.

If your getting the data noise right on the port then there isn't much you can do except swapping out boards.

Man I hate dealing with those 8 button A/B phones.