I've had my TL since November, 112k miles, I just got new continental DWS's and an alignment, and my car sways on the highway. I'll hold the steering wheel completely still and i'll still be moving back and forth, seemingly pushed side to side by the wind, but its only recently begun to happen. What could the problem be? My apologies if this is in another post or an obvious answer, I can never find anything using the search.

 

Are there rain grooves on the roadway? Look up Trameling

 

You should google any search you want to do for this site. Never use the search function, it's just a waste of time. Google it and go to the acurazine results, has always worked much better for me.

 

I think pohljm's post means to make sure you're not experiencing "tramlining" due to the road surface.

Assuming no tramlining and no bushing/suspension hardware problems, it sounds like the rear toe is off.
Do you have the alignment spec sheet for before and after?
If so, what are the specs on the rear toe following alignment?

 

The DWS has a soft sidewall and many complaints on handling, but none that mention the car sways back and forth, so don't know what air pressure you're using, but maybe try to add more air.

Years ago had a big Pontiac station wagon and threw some inexpensive tires on the car before resale, and on the highway the car would sway back and forth as the tire sidewalls weren't strong enough to keep the body straight and it was great in sweeping turns.

 

I checked the air pressure, and they're all around 35 psi except the front right at about 30. Although I had the tires changed at Belle Tire so they inflate the tires with Nitrogen, not sure if that would change anything.

And for the alignment, the rear toes were at -.11 and -.12 from left to right, and post-alignment were both set to -.01, the front right was my real problem before at -.28

I'm not extremely concerned because I'm not flying all over the highway, the sway is noticeable but minimal, I just want to make sure it isn't the start of something big and if it was I want to catch it before the damage is done.

 

now that you mention it I think I'm having the same deal with mine. I was on the highway and felt it sway a little, but I don't know if it was due to the light rain that just occurred recently..