Check tire balance, alignment, and suspension part wear.
-jeremy-

 

can you bounce your rear end like a basketball? sounds like your struts might be blown.

What do you mean by wobble and sway? When you take a hard left, does the right side seem to rise up? Lot of tire squeal? What tires are you running? As for wobbling, are you referring to steering wheel jittering at certain speeds, or just what seems to be lack of alignment? If it's the first one with jitters and shimmy, replace your steering rack bushings (12 bucks worth parts, but about an hour of labor and profuse swearing)

 

is your car lowered? sounds like a case of bumpsteer. Bumpsteer is when your wheel changes camber as your control arm moves up and down and your roll center has been changed due to lowering of the car... here's a fix from zhome.com

Basically it is a 3/4" thick aluminium spacer that mounts between the strut and the lower control arm, allowing the lower control arm to regain a somewhat horizontal position. The spacers that install between the strut housing and ball joint do not cure bumpsteer. I know that several vendors advertise them as doing bumpsteer spacers, but after I installed them, I found out that they do not cure it. They do give you a little negative camber and effectively raise front roll centre and these are good things to do to a lowered Z. The reason these spacers don't cure bump steer is that they don't address the problem. I looked into the definition of bumpsteer and found that is very well covered in (of all things) the Chevrolet Power Manual. Zero bumpsteer results when, on each side of the car, (a) the line connecting the tie-rod ends' centers and (b) the line connecting the inner control arm pivot centre and lower ball joint centre are parallel in the vertical plane and are of the same length. The problem on the Z is that they are not parallel. The bumpsteer spacers lower both the lower ball joint and the outer tie-rod end. Therefore, they don't change the non-parallelism of the lines (a) and (b) above. To fix the bumpsteer, you need to change the angle of one of these lines. An easy fix is (from "Datsun V8 Z conversion manual", by Mike Knell, Classic Motorbooks) to raise the control arm's inner pivot point on the crossmember. Here's how he does it: -Remove the doubler washer in the original crossmember hole with a chisel. -Drill a 9/16" hole in the crossmember 3/4" above the original hole. -Weld in a doubler plate for the new hole. -Grind the part of the control arm near the bushing to prevent interference with the crossmember. You can also raise the pivot by using the offset camber bushings, but when you change the position with these, you have to go back and adjust the toe-in. The spacers don't cure the problem, but it is possible for them to help. With lines a and b not parallel, there will be a position where they will be closest to parallel. If you lower a Z too far, you probably move it away from this ideal point, and get more bumpsteer. The manufacturers of the bumpsteer spacers are probably trying to get the tie rods and control arms back to their stock position so you will only have the stock amount of bumpsteer. (or slightly less because the stiffer suspension will move less over bumps). Another way I've seen on a 510 is to change the effective "length" of the control arm. Take two sets of control arms, cut them in half , then weld the 2 long halves together, thereby increasing the length of them. It also increased the negative camber and has worked like a charm for two auto-x seasons now.