Ok when I"m do close to 80 mph when I push on the gas the car shakes and when I let off It's nice and Smooth agian. Does anyone know what it could be?

 

wheels might need to be re-balanced

 

It could be that even when its smooth when I let off the gas

 

What model do you have? Need more info. Does the check engine light ever come on? Could be a vacuum leak possibly

 

cv joint? ^^^well its in 2.0 lsj so its a ss/sc^^^ or a swap which i highly doubt...

 

my one buddy cobalt does the same thing in only third gear around 80 it shakes a lot he thinks its the transmission he also revs to 7200...

 

its something they installed in your car to keep you going over the legal speed limit.

 

mine dosen't do that and i've been clear to 150

 

My **** does the same thing.. only its not as bad when i pound on it. only when i gradually accellerate

 

hmm could even be a bad motor mount then. My ss/sc has been to 145 and i have no shaking problems if its not a poorly balanced wheel the mounts would be my next guess along with a cv shaft

 

sarcasm>you...

p.s what reason did u have to go 150 on public roads?

 

ive seen it multiple times on the cobalt... im putting money on cv-joint

whatever reason he wanted speed limit fairy just f-in with ya

 

wouldn't the cv joints make a clicking noise when you turn sharp? I Just noticed that the guy I just got the car from has a bad bad setup that might be the problem that i will fix. He put a 2.7 pulley with 45# inject. and I think has still the stock tune

 

are you sure you aren't low in the RPMs and the engine is bogging or something weird. Try dropping it to 3rd and doing the same thing.

I get a lot of vibration when i push the gas in at low RPM due to now power.

 

I'm in 5th gear doing 80 and i just barley touch the gas not get on it and bog it.

 

You have to do it at least once otherwise you don't deserve to own one.

At 140+ (I didn't have the interceptor to mph but it was 140 downhill on the turnpike) things were shaking and the spoiler was hula-ing like a drunk fat girl at a theme party.