I have an 07 SS 2.4.

When I rev the car on neutral, everything is fine, the sound is nice and perfect.

I put myself into 1st gear, and then when I start off there is a vibration coming from under the car, I would say near the downpipe maybe.
I not only hear the vibration, I feel it pretty bad. It lasts until I reach about 1500 RPM and then goes away. I've had this when shifting into 2nd gear a few times also, but it's mainly in 1st gear.


FYI:
I have an LSJ downpipe
I have an aftermarket 2.5'' catback

I think that the exhaust touches the rear crossmember when I go over bumps; even though I installed it myself and it looks like it clears it by about 3 inches at the closest point. It makes a metal knocking noise.
Someone mentioned to me that it might be the bushing that is in the connection between the rear shock and the frame (I unbolted this to install my catback); so it might not be the exhaust.

 

u letting out the clutch too fast without enough gas and its stuttering to stay alive maybe? try pushing the gas pedal a bit more and maybe letting og of the clutch a little slower could just be the shudder from that

 

are you lowered?

 

no i'm not


it's not that, I know how to drive don't worry

It almost feels like the transmission is touching a motor mount at take off

 

well we know it is not the engine. it has to be in the driveline. is there any feedback in the steering wheel when it is vibrating?

 

no steering vibrations at all

the vibration is about twice as fast as the one you were referring to in ur first post

 

hmmm...well then it wouldnt be the axles cause you would feel that in the steering wheel...make sure none of the exhaust heat shield is hitting anything. other than that i dont know what it could be

 

don't really feel like laying down in the snow though....
I'm just hoping that the knocking and vibration are both due to the same thing

exhuast touching a heat shield could be an option you're right

it's weird that it only happens at take off and that if I rev at the same revolution at neutral it doesn't do it

 

That is what I was thinking.

Also has your car been in the snow and ice in Canada, and have you put it in a warm garage to un freeze it? Maybe you have an ice chunk somewhere?

 

I wish I had a garage ..... i could play in my car everyday
i shoudl go to the car wash, they have big jets washing under the car too as you enter sometimes, that could clear out all that crap

i'll go do that now actually, I have to go see my gf anyway

 

Yeah, it happens to me all the time in MN. The wheels get iced up and throws them out of balance, and you get bad shakes in the steering wheel.

 

Awhile ago someone had their downpipe hitting on a the front swaybar or something up there . The downpipe was hanging too low and he had the same problem.

 

ooo i have an idea how bout since your an 07 i assume you still have a war.? so i would just..... take it in instead of asking us about it since we obviously can't see or hear any of it

 

ummm his questions are kind of the main idea of what a forum is about

 

i get bad rattling with 3-4 people, depending on the weight, lowered on sportlines and 3" cat back, is this just the exhaust bouncing around under there?

 

pblm solved, it was my front exhaust hook that got punched out by a piece of ice I guess.
result: the catback was almost sitting on the crossmember, and the vibration could be felt all the way to the front.

I hooked it back and I have no more vibrations now