OK.. At this point it looks like you're just going to have to get the car in the air and do some troubleshooting yourself.


1. Wheels - Could be improperly balanced. That was my first thought, but you said "no". Moving on.
2. Tires - According to zakmartin's experience with these matters, I wouldn't write that possibility off yet. Make sure your lug-nuts are torqued down to spec. Not ruled out.
3. Brake Calipers - Could've been a possibility as well. When calipers stick they generate heat. You've ruled that out as well. Moving on.
4. Rotors - Could be a possibility if they're out-of-round. Usually felt at any speed over 10mph. Replaced 5k. ago. Ruled out. Moving on.
5. Wheel Bearings - Will definitely cause some vibration, and often accompanied by a rotational humming noise. Not ruled out.
6. Alignment - Alignment guy of 35yrs. say's ''All front end components are solid as a rock". Rule that out if you want.
7. Shocks/Springs/Struts - Again, ruled out by your alignment guy. Said, "Doesn't need them".
8. Steering - Zero dead spots, along with confirmation from your alignment guy that everything's "solid as a rock" up there(assuming he checked steering linkages).
9. Transmission Mounts - Worn mounts can cause vibration as the momentum of the driveshaft increases. Not ruled out.
10. Engine Mounts. Worn mounts can cause vibration as the momentum of the rotational mass increases. Not ruled out, but less likely to be it.
11. Out-Of-Round Driveshaft/Worn Driveline Components - Can definitely cause vibration. Typically felt before you reach 65mph. Not ruled out.
12. Rear Differential/Differential Bushing/Rear Axles - Worn differential components/out-of-round axle components will cause vibration. Check the fluid-filled differential bushing. If it's leaking, it needs replacement. None ruled out.


Enjoy your weekend. Good luck.

 

If you have a manual transmission, does it vibrate when you push the clutch in ?

If you have an automatic, can you put it in neutral and eliminate the vibration ?

 

Thank you to all for all the help. I'll let ya know what I find out.

 

112k miles on stock shocks? Inside tire wear? More so in the front rather than the rear? It's your shocks, I'm going through that right now because I need new shocks. It will only get worse in the next 10k miles.

Take it to another shop and ask them to check your suspension. I had my alignment guy as well tell me the shocks were fine. But I took it to another mechanic and they told me my shocks are just shot. And that's causing my tires to wear on the inside since the shocks can no longer support inner weight of the car, causing the tires to be pushed outwards. Which is causing uneven wear, which THEN causes the vibrations.

 

Generally, shops don't turn rotors anymore because they're just not built to be turned. Turning a used rotor will generally result in faster warpage (once the short-lived happy moment of having no brake modulation goes away).

If you haven't done so already, get the car up in the air and re-tighten the suspension components to spec and check all your bushings, end links, tie rods and ball joints.

 

Brake rotor modulation not germaine to the topic.

No updates to report.

 

Manual Shift. As I drive the car at 75 MPH, I can feel the vibration thru the gear shift lever. If I push the clutch in, the gear shifter no longer vibrates, and it seems that the vibration in the car is not as noticeable, but still there. So, as the car slows down, the vibration goes away (less) with the clutch disengaged.

I test drove a 2014 370Z yesterday and the difference, especially at higher speeds, was palpable. I

 

New shocks/struts...no difference.

 

I'm bringing this thread back from the dead for a good reason. Obviously because I'm having a similar issue.

Since I've got my Z +2 years ago, I've had this vibration pulsating through the car. I feel it in the floor, seat, slightly in the steering wheel. Keep in mind it's been happening since I bought her used at 112k miles. Now at 148k. Since then, she's gotten new wheels, tires, bushings, coilovers, brakes and rotors.

With all those possibilities eliminated, what could it be? I saw the options in the thread, but here's the catch:
-The vibration pulsates like a slow heartbeat for 1 second, goes away for one second, and so on.
-It moves from the steering wheel to the floor to the seat through each pulse.
- It happens at cruising speeds and highway speeds
-As speed increases/decreases, the rate of the pulse does not change. It remains 1 second intervals at all speeds. Therefore, I'm thinking it can't be something related to the suspension, axles, or hub bearings

Any help will be greatly appreciated!

 

My first corvette had a similar issue, I cant remember why right now, but I replaced the end links and it went away

 

Nice to talk to you again trav! I suspect something in the engine bay. What are your thoughts?

 

I mean anything is possible, engine mounts might be possibility, crank pulley/damper.

 

How would I go about visually inspecting the engine mounts?

 

How would I go about inspecting the engine mounts? And please don't just say "look at them"