There is a bushing the pushes the rack against the pinion. That might be worn/loose and can cause some slop.
There is also a spring that pushes the bushing against the rack, that should provide constant pressure, but springs give out from time to time.
If it is not in the rack, but higher in the column, then it could be the mounting point, or a bushing, or it could be the collapsible column is broken...
Take a look here