i've had this car since day one and have had a moderate vibration that comes on around 70 mph and peaks around 80mph. (from 80 on up it remains but gets no worse)

over the years i've rotated and replaced the tires and it still persists. when the clutch is pushed in the vibration remains the same. (should eliminate tranny issues?)

you can feel vibration in the steering wheel, seat and dash.

odd thing - the vibration is more pronounced when you accelerate HARD up to 70-80mph as opposed to normal acceleration. someone told me this is a good indicator it may be a drive shaft/u-joint issue?

i'd like nothing more than to once and for all figure this issue out and increase the fun factor of wringing this beast out by about 10x!

any help would be appreciated!

giff

 

That's a common problem with a lot of cars, including mine. I recommend 2 things: First, replace the u-joints. If that doesn't do it, swap in an aluminum driveshaft out of am Iroc or better yet a 4th gen LT1/LS1 car. I went with a 4th gen shaft and my vibration is GONE. When I pulled the steel shaft from my RS, it was all rusty and the u-joints were shot, which I'm sure contributed to the annoying vibrations. The car only has 83K on it.

That's what I'd do first....

Ed