> 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.

I'd like to hear from someone with a late model C4 that has
absolutely no vibration at 65-75mph like my 2003 C5. I've fought with
vibration in that speed range since my 1996 C4 was new, it's about
115K now. It seems like there's a body resonance that is always there
but strongly magnifies any problem. Mine seems to be towards the
front. Wheel balancing and tire changing make a difference but don't
eliminate the problem. The last round after the vibration got worse
replaced a worn ball joint which helped a lot. I drive the C4 to work
twice a week and the 65-75mph vibration is worse in the first few
miles and calms down as the tires warm up. It's almost as if the
tires take a set when they sit like old nylon belted tires did. This
is the same for Goodyear GSC's and Firestone Firehawks.
That being said, there are a lot of things about my C4 that I like
better than the C5. By all means, have the items mentioned elsewhere
in this thread checked in case there is something that needs attention
but don't worry about a little residual vibration. Nothing I've ever
driven is as comfortable cooking into a turn as a C4. Enjoy your new
vette.