I have an 18 Limited 4x4 with just over 70k miles. I’ve noticed that when I’m accelerating (pressing the gas) that I can feel a subtle vibration in my left foot, which is resting on the floor. When I take my foot off of the gas and coast, it goes away. It’s more noticeable between 30-50mph, but I can still feel it at other speeds. Because it doesn’t occur when I let my foot off of the gas, I’m assuming that I can rule out wheel bearing and unbalanced wheels. I also feel that if it was something like an exhaust leak the check engine light would come on. I have read numerous threads on the needle bearing, but the vibration doesn’t go away when I engage the 4wd system. I was thinking it was possibly the driveshaft, but I wouldn’t know how to tell if it’s damaged. Anyways, does anyone have any suggestions? Thanks!

Greasing the drive shafts wouldn't hurt and while you'are down there check for play by pulling and pushing the drive shaft. Also check the sway bar bushinges are in good order. Your vehicle is fairly young but check for play in the lca bushings.