I know there are tire/allignment related issues that can cause a shudder at freeway speeds. I don't think that is the problem. It seems to happen inconsistently, and only while pressing the gas. It stops as soon as you let your foot off the gas. Help?!
It only ever happens once you get above 70ish mph. It definitely isn't the road condition or tires. It only happens while pressing on the gas. It stops as soon as you release the pedal, even if you are still above 70. It doesn't happen every time you get to 70, even on the same trip. They were able to replicate it at the dealership and agreed that it was inconsistent, but they didn't have an answer about what is causing it.