Kind of slapped together
Join Date: Jan 2010
Location: Bossier City, LA
There will be some of that due to being rack and pinion - R&P has a low "irreversability" to it compared to the recirculating ball (Saginaw) design.
Also, if your toe isn't right, it can be grabby. Same for caster - positive caster will get the car going straight after a turn; negative will make it turn on every bump. Toe also affects steering the same way; toe out will make it dance like a cat on a hot tin roof.
As to "what parts worn" - dang near any of them. Sway bar not so much; that comes into play when the car is turning and transferring weight from one side to the other. But a worn ball joint (upper or lower), worn tie rod ends, worn shocks, over or under inflated tires, worn bushings - all of that can contribute by not keeping the front end in one "piece" during bumps (i.e., bushing shifts, angles shift, that shifts toe and/or camber and/or caster, car changes direction. Repeat for almost any other part.)