So heres the story for my '05 coupe:
After state inspection I threw a new set of Continental Extreme Contact DWS tires on my 19" factory wheels and took the car to Firestone in Norwich, CT for a quick alignment, which they screwed up. They did it again and although the car was tracking straight, something felt weird about the rear suspension. The best way to describe it was just a "squirrelly" feeling when going over bumps in the road. It was also getting some heavy vibration from the rear and, after a weekend of 1000 miles + driving, the rear tires were showing uneven wear that hadn't been there before.

After my frustration with the obvious incompetence of Firestone, I took the car to my local Infiniti dealer to correct my alignment issue and replace my now worn out rear tires (threw the same Continentals on the rear). The car has been to Infiniti 3 times now and is scheduled to go in for its fourth tomorrow. As of today, it was pulling to the right and the squirrelly rear feeling is back again. I have a hard time believing that the dealership would screw up the alignment three times consecutively, which is making me think that I may have some sort of problem with my rear suspension. A couple times after hitting highway bumps at 80 mph, the rear end has actually felt like it was about to slide before the tires' lateral grip kept it on the road. Certainly not the confidence inspiring handling I'm used to.

So the big question is what could possibly be going wrong? Is there something that Firestone could have screwed up completely/broken that would give me these symptoms? Has anybody else had this problem? Could it be that the dealership technicians are just that jacked up that they could screw this up three times? I haven't had a very good track record with Infiniti dealerships thus far.

Any input is appreciated. I'm in the Navy and this is my daily driver and don't have the time, money or patience to keep screwing around with this...

 

Did anything make the rear end feel better? If so, what changed? Why three visits to the dealer? Assuming your car hasn't been hit, this almost has to be a suspension geometry issue, but it might be worn springs, bushings, etc. too. I would not normally expect the looseness you seem to be describing with rear alignment alone.

 

Check and see if any of the suspension hardware is loose. sway bars, end links, etc...

The only time my rear end felt like that is when my struts were blown (was more of a swaying from side to side motion). Does your car feel squirrelly when making turns?

 

I would never go to Firestone or Infiniti for alignment issues which you obviously still have. Infiniti doesn't know squat about doing alignment right, you're wasting you time and $$. Find a qualified independent brake/alignment shop in you area, explain what you're experiencing and have them fix it. They haven't broken anything they just don't have the knowledge to adjust it correctly....kinda like a "monkey f^cking a football!"
Gary

 

The car feels OK through turns, but not like it should. I took a highway turn today at 70 that I've taken much faster but it felt like the car was on the verge of slipping out.

The first two times at the dealer the steering wheel came back crooked- the first very noticeable, probably 20-30 degrees to left of center. The second time was much less noticeable, but still noticeable. After all three alignments if I let go of the wheel the car would track right. After the second alignment I felt like my rear end "squirreliness" cleared up a bit but was definitely not 100%.

My service manager thinking aloud on the phone mentioned maybe it was tire drift from improperly manufactured tires. I think that is a bit far fetched seeing as how the car will pull right regardless of how fast its going. How big of a job would springs/bushings and/or sway bar issues be? I've already put $4000 of maintenance into this car this year and I'm getting pretty frustrated....

 

Wow how do you wear out tires with a treadwear of 540 in just 1000 miles?

 

After Infiniti aligned the car 5 times at two separate dealerships, the car still pulls left. They suspect something in the suspension is bent from a pot hole I hit and told me to take it to a body shop with frame alignment equipment to figure out whats wrong. This all sounds a little funny to me... Thoughts?

 

Read what I posted several days ago, that's your answer. A good alignment shop can tell if anything is bent or broken and align your car right!
Gary again