Took my coach in for an oil change yesterday, had the mechanic check the Evaporator hoses. Sure enough, the hose from the tank filler tube had a hole chewed by some hungry critter.
I suspect it started when a wayward armadillo kept trying to make his home under my dual wheels on the driver side while we were in FL for the winter. Don't know why it took so long for the problem to manifest itself unless I'm mistaken about who done it. We have some pesky coons in our summer campground on the Ohio River so it's possible I'm blaming the wrong culprit.
At any rate my problem is solved, no more loose gas cap warning.
Nick, Sharon and Fin the wonder dog.