Didn't you say you were running 32 PSI cold, in all four tires?
If so, given your rim widths, I don't think under inflation is the problem, but you could always increase the pressure a little to be sure. Try adding another 4 PSI (36 PSI cold) to see. I suspect that will be far too high, so assuming it doesn't help, you might also try dropping the pressure a couple pounds (to 30 PSI cold) just to see if it makes any difference.

Tire balance usually causes a vibration rather than making the car jerk jack and forth, but it DOES usually set in between 50 MPH and 70 MPH, so maybe ... I just don't see how balance could make the car self steer.

 

can someone sense the irony?...

*s2k sideways*? lol

 

LOL, yea, I noticed that too.

 

My car was doing the same on the freeway, but it was really windy. Maybe thats your problem, was it windy?

 

not windy enough so that it would impact my driving ..... i think im going back to the alignment guy so he can fix my toe settings ...

 

Another thing that it may be is when the mechanic put on the springs he didnt check to see which ones were for the front and rear... because they all looked the same .. maybe he put one front and one rear in the front??? i think i may have to double check that also cuz i know the spring rates are a bit different .... can that be the cause ?

 

Yes it certainly could, as a matter of fact there is a good chance that is your problem.....

 

If you didn't have enough forward caster, that would most definitely cause big time darting in all directions.

There are a number of reasons that can cause these symptoms. Incorrect toe settings, wheel alignment is out of square, worn out lower control arm bushing'(s) will make any car bounce to the left and to the right all over the road at freeway speed.

Prolly in mosts cases an alignment will cure most of the symptoms, but if car gets aligned and still doing the same thing, there are part'(s) that are worn out and need to be replaced.

 

Exactly! The first step is to make sure that the car is properly aligned. If that doesn't eleminate the problem then we'll have to look elsewhere.

A good alignment man will check for worn bushings, excessive play, and so on, during the alignment.

Always a good idea to get a print out of the before and after alignment specs (whenever possible).

 

Have you steering rack checked. S has power assisted rack and pinion steering that can be adjusted. Mine had similar symtoms once and that turned out to be the problem.