Vibrations between 70-80...what's the deal?

[SC and SHO Blazer]

I've had my 91 SHO for four years, and over the last year plus (FOR SOME STRANGE REASON) I've been getting a vibration while I drive. Now this vibration only...I mean ONLY occurs between the speeds of 70 and 80 mph. I'm tryin to find out what this could be. At 69mph...nuffin...at 81mph the vibration stops...I've gone as fast as 145mph since this and there is no vibration at those speeds.

Now, this started kinda out of the blue. I've done many mods/ upgrades/ suspension work. I've gotten Eibachs with KYBs all around, new Moog parts (inner and outer tie rods, lower control arms, end links, bushings). I have 17in wheels/tires which have been balance, and rebalanced and rebalanced again... they run smoothly on my 89 AND 93. I have not done my Subframe Bushings yet...which I think may be the problem, but I wanted to find out from other Taurus owners what my problem may be. I have a few friends that are having the same problem, but their's is not as drastic as mine. Help is needed! :hpoop:

Thanks.

James E.
[email protected]

 

[bmxludwig]

I had the same exact problem with my atx, but it stopped when I got new wheels and tires. I have no idea what it was, something with the wheels and tires though.

 

[wood_e]

tire/wheel imbalance