I've got a 1993 camaro z-28 with a 6-speed and it shakes very badly at higher speeds. 110 mph to be exact and in every gear (well, 3rd and 4th at least, I havn't tried over 100mph in 5th or 6th). It accelerates flawlessly up to 110 then does a really bad, forward-backward, shake (not like a misalignment vibration). It jerks like the ABS is freaking out or something and can probibly give whiplash (not a fun thing to happen at 110mph). What would cause that? I would really like it fixed since a Honda Civic with the hubcaps off, a wing, and a fart pipe loaded with five guys smoked me on the highway (not cool at all).

Also, my clutch "grinds" if i let it out higher than 1800 rpm in any gear (its the stock clutch with 126,000 miles on it) I will get the clutch replaced but added this incase the "shake" might have to do with the old clutch.

 

Did I stump ya?

-Top Speed governer?
-Unbalanced Driveshaft?
-Any Ideas anyone?

Hasn't anyone else had this problem or doens't anyone else have it?

 

'93s and '94s had a service bulletin on their driveshafts..." Vibrations at high speeds".. If its the original, that might be your problem... I bought an LPE aluminum 3.5in driveshaft for my '93.. Good price and saved weight from the steel original...

 

It sounds like you hit the top speed limiter. A friend of mine has a 97 Z28 that came with tires that were not Z rated. He had had the same fore/aft shaking experience at 110 mph.