Sounds like kick down linkage needs adjusted,mine will do the same thing if kickdown cable is set too tight.Are you running a stock linkage or a cable setup?
Stock linkage, and its been working fine for a couple years, just started doing this about a week ago. Also when I was on my ride today, I stopped several times and backed off the adjustment on my kickdown linkage, backed off to the point that it will not kick down when you floor it. And it made no difference as far as the weird shifting. That was one of my first thoughts, that maybe I had it set to tight.
