I'll have to dig out the invoice and get back to you. He replaced the ball joints as well so I'm not sure of the breakdown. As a side note, he replaced the ball joints first as they were loose but that did not fix the problem.

it sounds like a tire balance issue to me too..
it is fairly easy to figure out though, generally if it is a tire balance issue it will go away if you speed up like 10mph. So try going 85 or 90 and if it goes away, go get a good roadforce balance done and you should be fine

Yes exactly! It's smooth at first...sometimes throughout my morning commute(usually chilly temperatures), but in the afternoon or evening on my way home, I'll start to feel the slight vibration. I thought I was going nuts...I'm beginning to suspect the rotors. Although I don't have any pulsating brake pedal when cold or warm, hmmmm.

A bit more info. I noticed the other day on the way home from work that on long highway turns the vibrations seem to be reduced. This leads me to believe that it has something to do with the steering or at least the front end.

Anyone know how to diagnose compression rod bushing? I keep reading about these but not sure how to tell if they are bad.

Update. Had the tires balanced using a road force balance. Also had the front rotors turned.

This has made a big difference. Its not 100% better but it might be 75% better.

I can still feel a bit of a vibe in the rear. Might have the rear rotors turned as well.

Will keep everyone posted.

Ok so im not the only on same exact car. 2005 g35x 90k on it vibrations at high speed 80. I brought 4 new tires same problem i brought aftermarket slotted rotors same problem. I went to the dealer for a 80k check up they lubed up the joints check the shocks an bleed the brakes. The high speed shake from braking was gone an the shaking at 80 was too. Im thinking of doing new shocks an springs i live in nyc the city of potholes. An i will check the compression rod. suspension is all stock no crash only mods or engine.

I will be getting new tires and alignment next month, hoping it will fix the shimmy..... i did a rotation,, and its little better and pulling less...

just want to follow up with who ever has this problem, my 75+ vibration was fixed by replacing both compr bushings, having alignment done and roadforce balancing all 4 tires,,,, the car is now solid with no vibrations i had it up to 110 this morning,,, pass seat is also solid,,,,, before it was shaking badly and 100+ dash board (part that moves with steering wheel) was jumping like crazy too

This

http://www.tirerack.com/images/tires/vibechart.pdf

Well, I thought I was losing it, but this is happening to my 2005x as well. Anything over 65-70 and the passenger seat shakes and I can feel the vibration through the pedals. The tires are new, had it aligned and balanced....still happening. In the winter I get that nasty creaking sound from the front end when I pull into a driveway or go over a speed bump. I'm thinking compression rod bushings based on what I've read here. Drives me nuts. I'll let you know if this resolves the problem.

i have the same problem, i hate it! im gonna change my front rotors and pads soon and then get an alignment. Balanced the tires and it didnt fix the problem

Yep, I had the exact same issue.

balanced all 4 wheels and no vibration.

how much was it for the compression rod bushings?

i am starting to have this same issue...roadforce balance helped a bit but it is still there and is driving me NUTS as i crusie at 75-80 on the hwy... i sold my last car because of this exact issue

possibily there are dirts inside the break or you need alignment.

by the way. if this problem insist, i suggest taking to the shop since these two are the usual reasons