vibration at 80 mph, comes and goes
 

Issue: Vibration at 70+ mph just cruising.
Every couple of seconds i get this vibration. It comes and goes extremely consistently.

Possible problems: suspension wearing out? (08 with 80K+ miles, stock suspension)

This problem has only popped up after trailer-ing the car across country

Wheel and tires are 10.5 in the back 285/35/19 9.5 225/35/19 on the front


Thanks for the help in advance

tl;dr
Its not the tires (replaced with a brand new set)
Its not the suspension (new shocks)
Its not any of the brake components (new rotorsx2 and new pads)
had the car on the dyno and the right rear tire was tracking wierd (new tire)
While on the dyno car had a pretty visible bounce (wheel?) apart from curbing it one surely i would've felt this before hand...

Could be a loose wheel. I had the sme problem but after I did my brakes the front passenger rotor just fell off after taking the wheel off, I think it want sitting flush when the wheel was put back which caused the wheel to have play in it. I'd just make sure all your wheels are tight, and check to see if your bushings are good.

Interesting as I just had my brakes and rotors done. Time to buy a jack

You did something wrong if your rotor fell off when you took the wheel off.

The caliper and bracket should hold the rotor on.

How was it strapped down for the move?

Does the vibration completely go away for seconds at a time, or just fade then get louder?

is it steering wheel vibration? or the whole car vibrates?, one of possible causes is the wheel weight came off, its noticeable at right speeds. just one of the possibilities

Agree, and very likely depending on how the car was strapped down. Definitely a possibility.

Sorry I should have been more clear, I was changing the brake pads so the calipers were off, but everytimes ive done pads the rotors are usually corroded to the axle at least a little bit (i know its not a bad thing the rotor came off easy) but its possible it was not replaced flush the last time it was take off

It was on a uhaul car transport. all 4 wheels off the ground.

It doesnt completly go away just its very consistent, comes and goes every other second.

Not steering wheel vibration. Thats why it has me stumped. I can feel it most prominently through the gear knob. More of a whole car shake.

checked all the wheels, they are on tight. I hate shops that just go ham with their air tools. I couldn't get any of the 3 lugs off with a 4 way...insane

ok, if the vibration is That bad that it makes the whole car shake, then i d think it has to come from the engine as engines move in their motor mounts a bit but it can cause the whole car to feel it. mazda rx 8 has bad tranny mounts and that transmission is moving there quite a bit. so if i were u, i d check the motor and transmission mounts first, just to rule that out, next step would be is to provoke the shake, see if u can cause a condition that makes that shake, for example does it do it at any other gear in that speed at certain rmp, say if u were going in 4th at 80mph, or 5 at 80 or 6th at 80, then we can guess more:)

p.s.: or u can do that in reverse order

this is interesting, tell me more.

Might just be coincidental, I would go have your front tires rebalanced. A wheel weight may have fallen off.

I can feel it at a slower speed but the faster i go the more apparent it becomes.

I'll get a video sometime soon.

no real steering wheel vibration. I can feel it in my foot and butt the most.

Will have front wheels re balanced tomorrow.

is it manual? does it vibrate if u press and hold the clutch and put it in neutral while driving?

yes its manual.

only at speed do i get the wave like vibration.

tried to get a video last night but 80+mph in the rain on the highway doesnt work so well

very interesting, i ll sure wait for the video when ever u can shoot it, till then i ll think a bit more

https://*******/GuER

Try and watch the last 5 seconds of the vid.

My hand is gripping the shifter not very tightly. I can feel the same vibration in my butt and foot.

Look for a vibration the it stops for a second then vibrates again

dam did u tape the camera to ur head? hahaha, well the tranny gets its shake from the engine, but if u r feeling it all over the place, then i still say the motor/tranny mounts would be my primary guess. every ones shifter shakes, but i dont feel it in any other parts of my body other than the hand, and not even that bc i dont hold my hand on the shifter.

Haha! I had my hand on the shifter and was driving with my knee.

I had my go pro the night before but it was to dark/ to wet to film.
I was on my way to the airport and it was sunny and doing it.

If it was normal I would think it was a regular vibration and not intermittent.

I'll check out the motor mounts

i would check motor mounts, trans mounts, rear diff bushings, make sure nothing is wrapped around driveshaft.... just throwing out what i would check

sorry i haven't been updating this as i should.

I'm not 100% sure if i can check the motor mounts on my own so I will be taking it to a Z shop in town (nashville, tn) and seeing what they have to say.

I am going to be working two week straight out of town so the updates will be few and far between before i get back.

In saying that. What am I looking at to replace an engine and trans mounts?
parts plus labor? $350 - 400?

Thanks for all the help