I have an odd problem which I hope has a simple answer

Sometimes when on the Freeway going 80, if there is a left sweeping turn then goes straight my steerin wheel shakes. After a few miles or when there is a right sweeping turn then I straighten out the wheel shaking goes away. I'm going with this

I dont think its a balancing or alignment issue because that would be a constant shake right?

Could it be a motor or transmission mount, cv joints or what?

It's Funny though sometimes its smooth a butter and others it just shakes pretty rough.

I've also had a vibrating gas pedal issue for a long time but I've since given up trying to figure that one out (changed springs shocks wheels and tires and still does it)