Hello all! I've got about 1500 miles on my 08 GT now and this problem seems to be getting a little worse the more I drive it. When first driving after the car sits for a while the car will have some vibration in it, but after driving for a bit it goes away, which is what has confused me on it. I've had wheels out of balance before on cars and they just vibrated all the time, which this car is not doing at all. When I've been under the car when we were putting in the X pipe I saw the driveshaft on these for the first time and it looks like a horrible design. I'm wondering if thats the source of the vibration? Even if its not I plan on replacing it with a one piece ASAP. But anyways, any ideas on this is appreciated!

 

Hey JTE, welcome to the Forum.

I don't have much to help you with, only to point out that the "horrible design" (by which I'm assuming you mean its two-piece nature) was actually intended to reduce vibration (to my knowledge they used this basic design first in big trucks whose length required excessively long driveshafts that would whip around something awful: think of a jump rope and you get the idea). Of course, every engineer has good intentions and even when they're backed up by sound design there's no guarantee that the part might not have a manufacturing or installation error causing a problem that shouldn't be there. I just thought you should know.

For my 2 cents, I'd start looking elsewhere. The fact that it goes away after a bit points to some sort of "warm up" cause, only not in the engine. In the old days, tires would get flat spots in them if they sat in one place for too long, and as the tire warmed up from rolling it would work itself out of that flat spot. I thought that this problem had long since been exorcised by modern tire manufacturing methods, but I seem to recall someone making a comment about it recently. Maybe you could do a series of tests, using increasingly long intervals of the car sitting at rest until you begin to notice the problem. I would honestly be surprised if this was the cause, but it's worth a test.

Best,
-j

 

Have you checked the torque on your lugnuts?

It's possible they are a tad loose and the vibration goes away a bit when the wheels and hubs get hot and expand, taking up the slack.

Check your tire pressures.

Balancing was done at proper pressure. It's also possible that if your pressures are low enough, they are out of balance when cold, and you notice it less once the tires are up to temp.They would need to be significantly low, but it's a possibility.


My guess would be that it's both.

 

Yeah I'm a farmer so I'm used to dealing with the flat spots on our tractor tires, and that is exactly how it feels, like it flat spots from sitting. But like you Philostang I was also under the impression that modern tires didn't do that anymore on cars. Thanks for the ideas about this guys, I will check and see if any of these are what is causing my problems.

 

When I bought my 08 GT, it was riding really rough on the highway for the test drive because it had flat spots in the tires from sitting in the showroom. After driving it a couple of days, the vibrations went away. How often do you drive your car?

 

+1 - flat spots on the tires

I work from home and don't drive my car that often, but as soon as I do get it on the road, it does the same thing, but after sometime it goes away....nothingI cando about it, just something I have come to expect

Check your lugs, make sure your tires are properly baleanced, & make sure the tire pressure is correct.

 

My most recent tires on ALL my vehicles seem to have flat spots that round-out after a few miles, more so than tires I've bought years ago. I come to expect a bit of vibration until I've put a few miles under my belt, especially when the Stang has sat in the garage a few days or more than a week w/o being driven.