I took both seats out and inspected the seat rails (sliding mechanism). As one might expect, the passenger seat sliders are almost as new. Nice tight fit. No sloppiness at all. Different story on the driver's seat. I guess I will be ordering new slider mechanisms for the driver's seat.
Also took advantage of the seats being out to install the pool noodles. What a difference the noodle makes, and so easy. I would hate to explain their presence to the uninformed, but they really do firm up the seat nicely and unobtrusively.
The UPS driver is used to delivering many car parts from numerous vendors at our address. He was puzzled by the pool noodles, since we do not have a pool.
Thanks to Garry and others who discovered and shared this suggestion!
Lin