SilverBullet23

So I've got an 08 GT with about 160,000 miles on it. I've noticed recently a weird bounce or shake that seems to pretty consistently happen at lower speeds, usually like 20-30 mph, but also sometimes at higher speeds in the 40s. At first I thought it was just a bumpy road, but I feel like it happens way too consistently and on too many roads for it to be that. I got brand new tires, balanced, and an alignment not long ago so I don't think it's a tire issue. My theory is something loose or worn in the rear end. Anyone have any ideas on what it could be or what I could check, or could it just be inherent to the car with it having the solid rear axle?

tbar

My first thought with a bounce would be a bad tire. Even though you say they're fairly new I'd still take a good look at them. Getting a bad tire isn't that uncommon. Can you tell if it's in the front or the rear?

SilverBullet23

Pretty sure it's the rear. It did the same thing though before I got my new tires. It also has a tendency to be pretty shaky when I get up to highway speeds but then it smooths out without me doing anything after a few minutes. I don't know if these two things are related or not, but I feel like maybe they could be.

Norm Peterson

Sounds like they tend to flat-spot where the tire sits on the ground, and when it's cooler out they'll take a temporary 'set' in that shape that takes longer to go away.


Norm

JimC

What tires are they? Most modern tires don't flat spot sitting, but depending upon brand and model that can happen. But since it seems to be only the rear even with new tires, that suggests that it is suspension more than tires.

Have you changed your shocks and struts?That's a lot of miles on original parts.