Years ago mine felt that way. The fix for mine was a set of poly rack bushings.
Here is one set 4Runner Steering Rack Bushing Kit - Wheeler's Off-Road, Inc
It could also be upper or lower ball joints, or steering tierod ends (inner or outer), or the rack guide http://www.toyota-4runner.org/3rd-gen-t4rs/70884-how-replace-steering-rack-guide-pictures.html
Years ago mine felt that way. The fix for mine was a set of poly rack bushings.
Here is one set 4Runner Steering Rack Bushing Kit - Wheeler's Off-Road, Inc
It could also be upper or lower ball joints, or steering tierod ends (inner or outer), or the rack guide http://www.toyota-4runner.org/3rd-gen-t4rs/70884-how-replace-steering-rack-guide-pictures.html