I chased a vibration for a while in one of my cars. Did the usual. Replaced motor mounts, trans mount, U joints, balanced wheels & tires and even tried a different set of wheels & tires for a while. It turned out to be the crank damper. It was all dry rotted. When I took it off & replaced it with a new Pioneer damper all of the vibration went away. Then I noticed while sitting up on my shelf for several weeks the old damper had actually separated into two pieces while sitting so yeah, it was due to be replaced.