I had this problem with my 1999. It was a problem since I was towing a trailer across the country. I had replaced the tensioner (two or three times, a Chrysler rep insisted I need a factory original instead of the one from Genos, it made no differnce ) and tried many other things. A very good mechanic finally put a spacer washer in with the tensioner to set it a little further out. I have not had a problem since and it has been about three years. Why the tensioner needs to be further out now than it did before is still a mystery.
I wonder. Mine started after changing tenisoner, maybe should try the washer. Do you remember how thick a spacer?