Q.What Is Making My Pothos Plant’s Leaves Turn Yellow Between The Base Of The Plant And The Grown End?
I have had the plant for several years and the base plant’s leaves are healthy as in the growing end of the plant. It is the stems between where the leaves are turning yellow and falling off.

Certified GKH Gardening Expert
I am concerned about root rot. Check the roots for any mushy ones. Remove those if you find them and repot.
https://www.gardeningknowhow.com/houseplants/pothos/pothos-leaves-turning-yellow.htm
https://www.gardeningknowhow.com/houseplants/pothos/pothos-fertilizer-needs.htm