denn454

iTrader: (1)

I did a search for this and I didn't find anyone else with the same problem.

when going down the highway, between 55 and 65 I get a knocking noise. It sounds like its coming from the front left corner, but that could be my ears playing tricks on me. the sound is hollow, plastic sounding, and is at a high frequency. Its independent of engine rpm, so thats comforting to know its not in the engine.

has anyone else had this issue?

I do have ssc springs, I don't think it has anything to do with them, but i guess its possiable. I've went through the front supsension and everything is tight. I took off all the plastic engine covers and still no luck.

Apex

Did you recently switch wheels? If so (or even if not) get out a torque wrench and just make sure your lugs are tight. Happened to me when i switched back to my summers, they needed to get tightened again after 2 weeks of me putting em on and even tightening them 2 days after i put them on.

SC cobaltss15

is it throwing ur alignment off or anything? cause if sooo u could have something wrong with ur tire... i had a bad front end shake around 55 soo i took it in...and the guy was like yea ur missing 1/2 inch out of one of ur tires.. in one spot which is causing it to shake...i was like damn...got a new tire and everything was fine...

denn454

iTrader: (1)

its not a shake, I can't feel a thing. the noise is just loud enough to be noticed with the radio on, you can just barely hear it. with the radio off its pretty clear.

I have tightened the wheels, and all suspension parts.

It sounds to me like its something plastic, but it would have to be a hard plastic, or some light weight metal. it doesn't have a meatallic ting to it.

rukkee

iTrader: (3)

I had that noise and i noticed that the ECU was shaking in it's plastic bracket . It's right in front of the fuse box , wiggle yours and see if it moves alot .

denn454

iTrader: (1)

I just did a bunch of stuff, i put a clamp around the plastic cover that goes around the strut to keep it from bounding around. I screwed the inner fender wells to the frame to keep them from wiggiling. then I started hunting for more stuff, and I found the ecu was very loose. I took it out and found the back side of it very VERY scratched up, so I put some foam tape on it and i'm about to go see if that cured the problem. I'm thinking the ecu is the problem. Why did gm leave something like that so unsecured?

SC cobaltss15

was i the problem?

denn454

iTrader: (1)

I don't think you were the problem. maybe you were and I didn't know it.

the foam made a huge difference. I think I still hear a little something, but its so faint it could be my imagination.

I would say the problem is the ecu.

SC cobaltss15

lol sorry about tha typo. i meant to say wat was the problem?

denn454

iTrader: (1)

no luck finding the noise yet. I have tightened every nut and bolt in the front suspension, nothing was loose.

its not the computer
its not the inner finder wells
its not the hood shock
its not the engine cover

I'm out of ideas, and I can't replicate the sound without the car moving.

crash

is it the front strut/shock i think there was a problem with them before but why only between that speed who knows... i would check under the dash or in the little storage compartment to the left of the steering wheel and make sure nothing in there is causing it :p

denn454

iTrader: (1)

I've checked everything I can. as far as I can tell its from under the hood. its not only between 55 and 65, but thats the most common speeds. its a vibration thing. I heard it going very slow on a dirt road and also driving on ice when I hit the brakes.

Everything is logically telling me its in the suspension, but I've taken everything apart and put it back together and found absolutely nothing wrong. I'm about to put the suspension back to stock and take the car to the dealership and let them figure it out.

Am I the only one with this problem?

madmark

iTrader: (1)

cobalts are bad about the steering gear making noises. check and see if its leaking anywhere

denn454

iTrader: (1)

I'll check it out, but I haven't seen any fluids on the ground.

I'm beginning to think its coming from behind the dash. maybe its the loose nut behind the wheel, but there is no way to fix that.

madmark

iTrader: (1)

the other problem that is common is the column. its hard to find the exact noise without "rabbit ears" its a tool we use to trace noises

crash

haha if its still under warranty take it to the dealer ship like 10 times so that way once its out of warranty then it will fall under the pre existing condition that they did not fix before...