So I will assume that new steering rack bushings were installed at that time.
It could be anything from merely being out of alignment, to a worn out front end component. Like Jeno said, check your tie rods, ball joints, A-arm bushings, and the steering shaft, for any play.
These cars are getting to the age where it is a good idea to rebuild the entire front suspension when something wears out, rather than doing it piece by piece over the years. That way the car will at least drive as good as new... While the rest of it falls apart around you!