loss of signal -- "M.3.1.4"

After the recent floods (Louisiana, August), out TV reception got very dicey. Pixillated, then black screen with "no signal detected" message. Some improvement has been noted, and after a final "reset," all lines but one have returned to normal, The one line, however, has continued to deteriorate; now about half of the channels are black screen. It is also the longest line in the system, which makes me wonder if the soaking (both four-way and two-way splitters are pretty much weather exposed) might have damaged that particular connection. I have not experimented with switching splitter connections, maybe I should? The splitters are the standard Cox -3.5 db down, 5-1gig. Should I invest in higher quality splitters?

I apologize for the length of this message; but I am frustrated. Any suggestions will be maost appreciated. Thanks!