Alex wrote:
> My 94 convertable starts to vibrate around 65 mph.
>
> Feels like it is in the back of the car. Can feel it through the gear
> shift, so could it be drive shaft? Car is just at 100K.
>
> Recently acquired the car, first vette, so no history on the car and not
> sure where to start looking.
>
> Is this a common problem, or do I just go through the check the tire
> balance, rim straightness, etc. routine?
>
> Everything feels tight. No clunking on acceleration or deceleration, so at
> this point I don't suspect U-joints.
>
> Ideas anyone?
>
> Thanks!
>
> Alex

Welcome and enjoy!

Sixty-five is a typical speed for a C4 tire
balance problem to raise its ugly face.

You 'to-do' list looks good. Add the following:

Assuming you have the orginal factory wheels,
check to see if some well-meaning grease
monkey rotated wheels front to rear.

The original tire sizes were 255/45 on the
front and 285/40 on the rear.
--
pj