Let me start by saying i have done a good amount of searching on this subject. It seems there have been a few people with similar problems on this board, yet few solutions are every posted. So i present my case in hopes that some with similar issues or solutions may step forward and share.

Vehicle is a 2005 G35x with 77k miles. I am currently experiencing vibrations on the highway at 75mph and above. The ride is quite smooth at 70mph but thats were it stops. I haven't tested the upper limit of the vibrations. This is a bit annoying since i commute 100 miles per day. Most vibrations can be felt through the steering wheel.

I have recently replaced my driver front wheel bearing since it started to make noise. This i hoped would fix my vibrations. It did not. Before this i had my tires balanced and rotated. I also hoped this would help. It did not.

I find that if i lift off the throttle slightly i get a more intense vibration, which seems to lessen if i reapply the throttle or completely lift off the throttle. I have also noticed my brakes pulse slightly at highway speeds. This doesnt happen at lower speeds.

My guesses. Could be a front cv shaft. Could be a front steering component. Could be the front brake rotors. I would hate to just start throwing parts at it without some reassurance. I dont believe that it is coming from the back of the vehicle.

Any input or suggestions would be greatly appreciated. Any solutions others have found would be even more appreciated. I have a garage full of tools waiting to solve this issue, not a pocket full of money.

Thanks in advance.

 

Do you have after market wheels on the car ...

i had the same problems with my car around same speeds and it was because i didn't have hub-centric rings in my wheels as well as the same problems with the breaks .. also my rotors went back due to vibrations in the front as well and replaced them and break pads... and everything went back to normal

so do this ...
- check rotors
- hub-centric rings (maybe) depending on after market wheels

maybe / maybe not be the problem but those are really the only thing i can think of besides the alignment wasn't done correctly..

these are my guesses but wait a little for other to chime in


hope everything works out for you man and welcome to driver :-)

 

first of did you buy your care used? do you know if its a salvage title? it could have had front end damage and thrown the alignment off...IMO opinion this really sounds like your car isnt aligned correctly.

 

hmm, i just changed all of my four wheel bearings about a couple weeks ago. I started feeling some vibrations also at around 70-ish mph. Is it possible that the alignment shifts or changes when changing wheel bearings? But to the OP about your brakes pulsating when applied at high speeds is the definite cause of a slightly warped rotors. This may be causing your vibration also since brake pads are in contact with the rotors are all times. As for me, I don't have the pulsating brake problem so I'm not exactly sure what's causing mine.

I'm getting new tires and adjusting my coilovers, and then an alignment soon so I may never pin point the cause.

 

Could be alignment - could also be worn bushings from the front lower control arms or the compression rods.

 

I also have this problem, But my vibration is coming in the passenger seat...? Everything else rides smooth, but when no one is sitting in the Pass seat, looks like the back is doing the cupid shuffle! When I put my arm across and rest it on the head rest, the vibration stops....Any Ideas as what this could be?

 

I sure hope not.

 

All stock. No aftermarket wheels. Car was bought used. Not salvage. No wreck. Put 10k miles on the car and the vibrations are a recent thing. Car had an alignment at 50k i believe. Tires also only have 12k miles on them.

I think my passenger seat shakes too but that is most likely to the said vibrations.

 

I'm thinking i might have my rotors turned. The pads looked like they had a ton of life left in them. Could be a cheap fix and would definitely fix the pulsing brakes.

 

I recently experienced vibrations over 60 mph and passenger seat shake as well. Both issues were solved by replacing the compression rod on the drivers side. 2005 G35x.

 

During my morning commute i paid close attention as close as possible to the car. It seemed like the ride was completely smooth for the first 10 or 15 miles regardless of speed.

After about half way through the commute i noticed the passenger seat start to shake. Then came the vibrations above 70mph. This continued for the rest of the ride.

Seems like it could be something that starts to caused vibrations after it warms up. Maybe the rotors?

How can one diagnose the compression rods?

 

Good to hear that replacing the compression rods fixed your issue. My passenger seat shakes like a **** at high speeds too. My compression rod bushings are shot, and I'm trying to find a vedor that has the SPL compression rod bushings in stock. Unfortunately, it looks like their on backorder for now.

 

I had the same problem when I speed up the vibration would go away, and when I slow down or stay at the same speed the vibration would come back. The dealer said it was my drivers side engine mount. I replaced it and no more vibration.

 

I have exact same problem on exact same car @82K... shimmy,,.... i did rebalance of 2 front wheels and it did smothed it a little.... (i sold my honda because i could not get rid of the shimmy at high speed and was upset to get a g35 that has the same problem,.,,,

if your tires are still good find a shop with roadforce balance and balance all 4 tires,,, make sure they do ROADFORCE BALANCE,,,, it did a great job on my es300 when balanced at the dealer and other shops with crapy balancer just made my lex shimmy like hell.... check you alignment too ,,, My tire are at 3/32 so i'll wait untill sept-oct and will replace all 4 and do alignment (it pulls to the right)

have them check wheels for out of round and if one is have them replace with your spare rim ,,,, if 2 are bent have the best ones on front and bent ones moved to the rear.....

I had my on the lift yesterday and they checked for any play in the front and it was OK... no problems,,, may be wash inside of rims just in case to make sure no dirt can cause this shimmy....

bwt my shimmy starts at 75mph and never ends ,,, i tried 110 just getting even worve......

i belive the tires are the main cause and not the susp parts.... alignment comes second

 

how much was parts and labor?


my seat shakes too over 75mph