Sorry to say but you're going to need to do more work to eliminate that. Here is a list of things I've done to tighten up my steering A LOT from what it used to be. Still a little shaky but far more bearable to drive. I used to stab the gas pedal over bumps and the steering wheel would be out of control. Big heavy tires don't help either
Poly Whiteline LCA bushings
Poly steering rack bushings with 1/2" bolts
Removed rag joint from steering shaft
New tie rod ends
More caster
Next step will be a new steering pump as mine has over 200k miles.