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Shaking at high speed (90mph)

Runvsofthisbull

Well-Known Member
Donator
Hey guys I have a problem. When my car hits approximately 90mph it shakes violently. Now I have a 02 GT with a tubular k member and a arms. It's always done this since I swapped out the 3.8l that used to reside in it, but I'm wondering why? The 4.6 SOHC from an 00 GT is just bolt ons, but my suspension Includes a PA racing k member and a arms, steeda comp springs, mm subframe connectors, tokico shocks/strus, and mm cc plates.The alignment is good, tires are balanced (245/45/17s), but at 85-90mph the shake is really bad? Ideas as to what's causing this? I do have my stock a arms and will be putting them back in with steeda x2 balljoints and bump steer kit, not that I think those two parts are the major issue, but perhaps the a arms? I also post on mustang evolution and posted there and they said to have my car road force tested? Anything else/ideas you guys can think of? Please help if you can and or have had this issue before.
 

wickedstangs

Chula Vista, CA
Staff member
Administrator
what drive shaft are you using? I lost the welded on weight on my aluminum draft shaft one time and it used to do that...
 

Mustangcwo

Crew Chief
Staff member
Board Member
Then it's the front end of the car. Does it shake at all when you brake hard or just at high speeds. If it's high speeds, it more then likely the tires are junk. If it was ball joints, they would clunk and the lower control arms should not cause this condition either. The bump steer kit is an awesome idea and you should get it installed to improveyour steering angle. One last thing to verify is the rack and pinion. If the joints are getting loose on the rack and pinion, it can cause a shake.

What I would do is switch my tires with someone else and see if the condition persists. That will rule out the wheels and tires and wont cost a dime.
 

Runvsofthisbull

Well-Known Member
Donator
Cool thanks a lot man. The tires have good tread but perhaps they just get out of balance at High speeds. It does shake when I brake hard also but that I know has got to be my rotors, but regardless as soon as I hit about 90mph the car gets really shaky. I fixed up my old a arms with new prothane bushings and steeda X2 balljoints so I'm going to swap them back on as well as install the bump steer kit and new bushings for the sway bar cuz in addition to the shaking all the time the car makes an awful screeching noise when turning and when I hit bumps/dips in the road. All things considered maybe I'll veer away from hankook when I get new tires. Perhaps z rated this time.
 
I had a ford f150 that did the something. Took it to ford and they had to replace the steering damper. At high speeds it would start shaking so crazy that the dash looked like it was about to come off. My dad said while he was driving next to me, it looked like the truck was "running" down the road. not saying that's it's but possible with ford
 
Another term for it is steering stabilizer. Pretty much it helps to keep your tires moving the right direction. Like ones not turning left while the other is going right. There's better descriptions on YouTube. Even a video of people that put cameras on outside of there vehicle to record it.
 
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