I checked both ends of both shift cables and all seemed well. When I raised the leather boot over the shift lever, I noticed a long piece of black plastic that could easily have been wedgeing into the left side of the shifter base swivel. That would have prevented me from moving the lever enough to the left to open the gate into first and second; it was the end of the tie that secures the leather to the shift lever. I cut it off and shifting seems to be working well.
On the other hand, I may be playing a mind-game with myself! :rolleyes: I am convinced the problem is heat related and keep waiting for the problem to arise again.

Is there any adjustment on the side-to-side cable?