What does my LeSabre shake and shudder?

If it keeps getting worse at higher speeds> alignment. If it smooths out above the range of vibration> wheel balancing. If it only vibrates when accelerating (usually in the higher gears)> probably motor mounts.

i had same problem checked motor mounts they were good so i done a tuneup and it got better but still not completly fixed only does it in overdrive when going up any hill

anyone have any other idea what might be wrong doesn't act like unbalanced wheel as it stops after 60mphish or higher or if i shift down

Sorry, still sounds like the front motor mount to me. In overdrive there is more load on the engine and it tends to tilt up in front. If the motor mount is cracked, it allows too much tilt in the engine and causes it to throw your alignment out by repositioning the transaxles. If you down shift it reduces the load. Did you remove the mount any visibly check it for cracks?

Oops, meant and, not any. Any action increasing torque on the engine, accelerating, being in a higher gear, trying to maintain speed going uphill, etc. Your tuneup probably increased your power and made it react less to the increased load. Other than that, I am out of guesses.

CV Axle Joint

I have a 1998 buick LeSabre and the front driver wheel got a slight tilt out

a front wheel on the driver side is tilted out in my passenger side wheel is tilted in what can cause that problem on a 98 Buick LeSabre custom front wheel drive

So I have a 2002 Buick LeSabre and I also have a shake at 70 mph and faster. I have changed cv axle, lower control arm, wheel bearing and balanced all 4 wheels. All this in the last 3 weeks. I still have the vibration. Does anyone know what can be causing this??? Please help and thanks.