Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i start?
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Supreme Member


Joined: Apr 2010
Posts: 1,027
Likes: 11
From: Modesto, California
Car: 88 Firebird Formula
Engine: LO5 5.7 TBI/Ebl Flash
Transmission: 700R4
Axle/Gears: 2.73 stock rear end
Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i start?
So Ive owned this car for 5 years now and ive never done any suspension work. The first 3 years of me owning the car it was my DD and it got driven alot. I was able to take it on good 2hr drives to areas around my city (Bay area, fresno/visalia, Sac) with no problems. I mean yeah the car was pretty bouncing and didnt like potholes/bumps and it was a bad drive, but not anything near as it is now. Now after sitting for 2-1/2 years, at city speeds it drives fine, but once i hop on the freeway it feels really unsafe. Ive only driven it on the freeway for about 5mins or less a handful of times, and in that time its very shaky at 60-65mph, feels really unstable and off. It was un touched suspension steering before hand but now its just GONE! Ive been driving this thing alot for the passed 2-1/2 months and did alot of engine bay maintenance still no suspension/steering work. I was already advised i should rebuild my steering which is definitely on the list (center link,tie rods, idler arm, ect) but how can i get my freeway speeds a little more 'stable' feeling? it just feels so crazy in there!@!!!!
Any Information or Advice is greatly appreciated!!! Thanks guys
Any Information or Advice is greatly appreciated!!! Thanks guys
Re: Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i st
tires prolly took a set from sitting for so long without moving. in other words a flat spot.
if they are unknown tires check depth of treads they just might be shot as well. older tires that have seen a lot of use will develop flat spots pretty easy and may or may not even out on use.
other than that check the hardware connecting everything up.
if they are unknown tires check depth of treads they just might be shot as well. older tires that have seen a lot of use will develop flat spots pretty easy and may or may not even out on use.
other than that check the hardware connecting everything up.
Thread Starter
Supreme Member


Joined: Apr 2010
Posts: 1,027
Likes: 11
From: Modesto, California
Car: 88 Firebird Formula
Engine: LO5 5.7 TBI/Ebl Flash
Transmission: 700R4
Axle/Gears: 2.73 stock rear end
Re: Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i st
tires prolly took a set from sitting for so long without moving. in other words a flat spot.
if they are unknown tires check depth of treads they just might be shot as well. older tires that have seen a lot of use will develop flat spots pretty easy and may or may not even out on use.
other than that check the hardware connecting everything up.
if they are unknown tires check depth of treads they just might be shot as well. older tires that have seen a lot of use will develop flat spots pretty easy and may or may not even out on use.
other than that check the hardware connecting everything up.
Member

Joined: May 2006
Posts: 378
Likes: 8
From: Columbus, OH
Car: '87 IROC-Z
Engine: TPI 5.7
Transmission: T-56
Re: Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i st
So it has been 2 1/2 months. What I found after taking my car out of storage after 8 years is that they were flatspotted, but I aired them up to 45-50 pounds then had it towed to the shop so that they could get it running again. In those 2-3 months at 45psi the flatspotting went away. The tires are Dunlop SP8000s from 2000.
Thread Starter
Supreme Member


Joined: Apr 2010
Posts: 1,027
Likes: 11
From: Modesto, California
Car: 88 Firebird Formula
Engine: LO5 5.7 TBI/Ebl Flash
Transmission: 700R4
Axle/Gears: 2.73 stock rear end
Re: Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i st
So it has been 2 1/2 months. What I found after taking my car out of storage after 8 years is that they were flatspotted, but I aired them up to 45-50 pounds then had it towed to the shop so that they could get it running again. In those 2-3 months at 45psi the flatspotting went away. The tires are Dunlop SP8000s from 2000.
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Joined: Apr 2013
Posts: 71
Likes: 1
Car: '84 Berlinetta T-Top
Engine: 305 V8 LG4
Transmission: 700R4
Axle/Gears: 3.08
Re: Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i st
Could still be flat spots. My car was stored for 12 years. I had a similar issue with my car. I ended up rebuilding the front end and replaced my shocks and struts, my car was much more stable after that. I also had to put new tires on, but I waited till I had the instabilitiy fixed.
If the tires are flatspotted, they could develop a seperation in the layers of rubber causing them to fail. Tires have a shelf life too, regerdless of how much they cost. Sometimes it's best to just change them anyway.
If you feel a vibration you could check wheel balance. If it feels like the car is floating then check the shocks and struts. Flat spots feel like you are running over a water hose every few feet or so and may sound like a thud thud thud, kinda thing. Hard to describe really you just have feel it.
Hope this helps.
If the tires are flatspotted, they could develop a seperation in the layers of rubber causing them to fail. Tires have a shelf life too, regerdless of how much they cost. Sometimes it's best to just change them anyway.
If you feel a vibration you could check wheel balance. If it feels like the car is floating then check the shocks and struts. Flat spots feel like you are running over a water hose every few feet or so and may sound like a thud thud thud, kinda thing. Hard to describe really you just have feel it.
Hope this helps.
Last edited by StealthESW; May 27, 2014 at 10:15 PM. Reason: spelling
Member

Joined: May 2006
Posts: 378
Likes: 8
From: Columbus, OH
Car: '87 IROC-Z
Engine: TPI 5.7
Transmission: T-56
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Thread Starter
Supreme Member


Joined: Apr 2010
Posts: 1,027
Likes: 11
From: Modesto, California
Car: 88 Firebird Formula
Engine: LO5 5.7 TBI/Ebl Flash
Transmission: 700R4
Axle/Gears: 2.73 stock rear end
Re: Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i st
Could still be flat spots. My car was stored for 12 years. I had a similar issue with my car. I ended up rebuilding the front end and replaced my shocks and struts, my car was much more stable after that. I also had to put new tires on, but I waited till I had the instabilitiy fixed.
If the tires are flatspotted, they could develop a seperation in the layers of rubber causing them to fail. Tires have a shelf life too, regerdless of how much they cost. Sometimes it's best to just change them anyway.
If you feel a vibration you could check wheel balance. If it feels like the car is floating then check the shocks and struts. Flat spots feel like you are running over a water hose every few feet or so and may sound like a thud thud thud, kinda thing. Hard to describe really you just have feel it.
Hope this helps.
If the tires are flatspotted, they could develop a seperation in the layers of rubber causing them to fail. Tires have a shelf life too, regerdless of how much they cost. Sometimes it's best to just change them anyway.
If you feel a vibration you could check wheel balance. If it feels like the car is floating then check the shocks and struts. Flat spots feel like you are running over a water hose every few feet or so and may sound like a thud thud thud, kinda thing. Hard to describe really you just have feel it.
Hope this helps.
Sorry about that! Yes been constantly for about 3months now.
Junior Member

Joined: Dec 2008
Posts: 44
Likes: 7
From: Dallas, TX
Car: 1985 Camaro SC F41
Engine: ZZ4
Transmission: 700r4
Axle/Gears: 3.42 Posi
Re: Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i st
Take the car to a shop and have the front end checked. Most likely you have some worn out parts. Pull your wheels and check your shocks and struts, most likely they're old worn out as well.
Thread Starter
Supreme Member


Joined: Apr 2010
Posts: 1,027
Likes: 11
From: Modesto, California
Car: 88 Firebird Formula
Engine: LO5 5.7 TBI/Ebl Flash
Transmission: 700R4
Axle/Gears: 2.73 stock rear end
Re: Very Shaky/Unstable at highway speeds after sitting for 2years; Where should i st
Oh yeah i know my suspension/steering needs all new components. BUT i think i was drunk of my *** or on a really bad spot of the freeway the other day because ive driven it on the freeway a couple times now and haven taken it up to 90+ and it doesnt feel like that anymore. dunno maybe i just worn it in and its ok again. Like i said this past week or so has been completely daily driver and the first and multiple times now on the freeway since about 3years. When i first started driving it about 3months ago when i would attempt to do a U-turn in a street or a court i would hear moans and groans when turned all the way, but after driving it for a couple weeks here and there it went away? Maybe same thing here lol.
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