Check to be sure the steering gear is on "center point" with the wheels pointed straight ahead. If it's even a little bit off center there will be just enough slack in the steering gear to allow the wheels to follow slight imperfections in the road surface. Center point is checked using an inch-lb. torque wrench on the steering wheel nut with the Pitman arm disconnected from the tie rods and adjusting the sector gear preload until there's a 10 inch-lb. rise in turning torque as the wheel passes over center. Then reconnect the tie rods and adjust them so the wheels point straight ahead with the steering gear centered up.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!