I've checked all the tires, the brakes, the suspension components, the struts and rear shocks and springs. When it goes down the road, slow or fast speeds, it feels like there's a flat spot in a tire, I mean it's really shaking. It started only recently, and I don't recall hitting any potholes or anything. The tires all rotate smoothly, I've grabbed all of them and gave them a shake top and bottom, and on the sides, and they are solid. The upper strut mounts are solid. I even tried changing the tires front to back. What am I missing? Engine mounts? Dog bone? Clutch? Does this sound familiar to anyone?