I found this forum while searching the web for info about a vibration at freeway speeds.

Sounds like I'm far from the first with this issue which doesn't seem to have a definite cure. I finally replaced the original tires a couple months ago thinking that was my problem, NOT.

This is my second Caddy. First was a triple-blue 81 Sedan with the V-8-6-4.

I had 2 Olds 98's between the Caddy's but when they quit making them, the Caddy was my only choice.