06 Cobalt Shakes Violently on High Speeds HELP!!!

Hello everyone,
I'm not sure this is where I need to be posting this. I don't typically post on forums but I am at a complete loss with my poor car.
About a month ago my car went in for the ignition switch recall, cylinder recall and shifter recall. Ever since then I have been having issues with my Cobalt. I drive on the high way all the time so this is a huge deal for me.
After going at high speeds (typically 60 seems to be the sweet spot for the issue) for about 20+ minutes my car will get real loud road noise and then all of a sudden it starts to violently shake as if the wheels are going to fall off. Then shortly after my steering wheel will violently shake (I'm assuming because of the vibration in the suspension). I have taken it to the dealer and to a garage.
We originally thought it was the calipers sticking, so we replaced the calipers, brakes, and rotors just to be safe. It drove fine for a couple days and it did it again, so we took it to the dealer. Dealer said it was the control arms that go into the wheels and sway bar links. Replaced those as well. It happened again a few days later. Then we thought it was the wheel bearings and replaced both. That did nothing. So I thought my wheels were out of balanced. We took it to the garage to get them balanced and then rotated. That didn't work (it seem to make it worse actually). I then took it for an alignment.

I am at a complete loss. I recorded it because it never seems to happen when any one else is in the car. Please refer to my YouTube video.

HELP!!!
https://www.youtube.com/watch?v=AMpMLxuxabE&list=UUACR8sgBOsP-Ft4YO5po6cA

I would not consider that a violent shaking. If rebalancing and rotating the tires didn't work, and made the problem WORSE, it means you need to revisit the tires and wheels.

If one of the wheels is slightly out of round, or one of the tires has a minor tweak to it, it will AMPLIFY when moved to the front. What this is telling me is the problem tire WAS on the rear and is NOW on the front. Swap the tires on ONE SIDE of the car front to rear. Lets say you do the right side. If the vibration gets less noticable, the tire/wheel that is now on the right rear is the problem. If it stays the same, it is your left front tire or wheel, try swapping it to the back again to confirm. Have the problem tire removed from the rim and inspect both tire and rim thoroughly. You may find there is a bulge on the INSIDE of the tire that signifies a broken belt or a worn spot or other problem. You may find there is a ding or wave in the wheel rim.

At any rate, the reason the ignition switch recall made this problem worse is that they had to take the whole column apart to replace the switch and make any other needed repairs. They probably nicked a bearing or didn't tighten things down. So AFTER you take care of the vibration issue (because that "loose" steering column will help you find it), go back to the dealer and tell them to check their work.

We just bought brand new tires for it and now it is happening more often. We originally had snow tires on it(I think allowing for more of a cushion) and now we put all season tires on it. We took it to the dealer and my wheels are bent badly. We are buying new wheels and hope this is the problem. Thanks for your help and will report back.

vanessaz said:

We just bought brand new tires for it and now it is happening more often. We originally had snow tires on it(I think allowing for more of a cushion) and now we put all season tires on it. We took it to the dealer and my wheels are bent badly. We are buying new wheels and hope this is the problem. Thanks for your help and will report back.

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Did you ever find a solution? All these cars have this problem, including mine with 50k miles. I'm trying to find out what the problem is so I can quit throwing money at mine.