Worn ball joints, worn or out of adjustment wheel bearings, worn or damaged inner & outer tie rods at the steering rack assy., deteriorated mount bushings holding the rack assy. to the K member, insufficient preload on the pinion bearing, excessive lash between pinion gear and rack rod, steering coupler split & deteriorated, bent or damaged wheel, wheel & tire assy. out of balance, worn or deteriorated control arm bushings, weak or fatigued shock struts.
What did I forget ?
* Grab your steering shaft below the coupler, rotate shaft and note if the rack shifts laterally while turning. Movement of the rack here shows bad rack mounting bushings. R & Rpl., recheck toe in-out settings afterwards.
* Up jack the Z, place on safety stands.
Perform a looseness check at the front wheels, grabbing @ 12/6 O-clock check for play in the wheel bearings and ball joints. Change to 9/3 O-clock position checking for play relative to steering rack and tie rods. Wiggling wheel assy. slowly to check for play in noted parts.
Be sure that your lugnuts are NISSAN, and not some aftermarket BS. That was the problem with my 77. The problem had been there since I bought the car 3 years ago, and had been fighting with it ever since (tires, wheels, poly susp added, tie rods, ball joints, alignment, countless inspecting, etc) Now, it is GONE, just by simply putting the correct NISSAN lugnuts on it!!