The memory seats that have the glide to enter/exit feature are supposed to be able
to move 2.125 inches backwards when you start the car, or the key is removed.
If you are tall, and you have your seat too far back for more leg room, the sliding
feature will not work for you if the seat can't move that 2.125 inches back.
I have the same problem you do from time to time. I am 6 feet tall, and I have my
seat set right around that magic number where it will glide back for awhile, and then
stop working.
No power memory seat, or any other power memory item for that matter, will always go
back to EXACTLY the same spot every single time.
Over time, it moves a smidge out of where you have it set, and all those smidges start to
add up to the point where your memory seat, or mirrors, or whatever are no longer in
the spot you want them.
You are going to have to adjust your seat so that you have at least 2.125 inches
for it to be able to move backwards, or its just not going to work. Your owners
manual actually goes into detail about this.
Now, if your on the shorter side, and you do not have the seat almost all the
way back for leg room, then you have a mechanical problem, which will
require an actual replacement of the seat electronics.
But I bet it stops working because you have it set too far back.
Jim