If it is the rack it will slop around if you jack up both front wheels so they are suspended and free to turn, then grasp one, then the other, and try and move the wheel assembly from the ground in a left to right arc, back and forth, just as if it were being turned by the steering wheel. Watch the tie rods at both the wheel end and at the inside boots where they go into the rack assembly. Many times you can just grab the tie rod and wiggle it around and determine the source of the problem.
Most often the tie rod ends fail, or one of the bolts on where the outer end connects to the wheel assembly works loose. They are easy to replace and I always use John Deere spray on graphite paint to lube up my new ones instead of grease. I respray them a couple of times a year. I buy my joints themselves from aftermarket sources.
If the rack fails you likely will see the steering wheel jump in and out just ever so slightly as you try to swing the wheels back and forth, or the rack will flop up and down in the housing just inside where the inside tie rod attaches one or both sides. You almost always have to pull the tie rod boots off the rack to see that end move.
The repair manual provides the best instructions for the novice to pop the rack out.
If the rack is shot beyond just cleaning and greasing, try to locate a steering rack rebuilder. The cost to rebuild one is about 20-50% of the price of a new one. The rebuilders generally install a grease zerk, and that allows you to lubricate it and keep it working like new pretty much forever after than.