Wondering what might cause this... My wife and I have both experienced it in my 2010 Tundra; she noticed it months ago, and I finally felt it this past weekend. I drove it an hour plus to go someplace, and shut it down for a few hours. On the return drive, about halfway, it decided to shake for a mile or two. Then it stopped. I had changed highways and I probably used the brakes, put a bit of heat into them, but nothing excessive, nothing different than on the drive out. I'm thinking it has a bad caliper but wondering if it might possibly be something else. It does not do this around town, and I've yet to notice any difference in heat at the wheels. [Unfortunately I did not stop on the highway to check.] I did replace a rear caliper a year ago, and when it went, it did act just like this, where I would get a shake. But when that caliper went, it dragged all the time and I could feel the power loss. I don't feel any loss and I still haven't found a brake that drags. Maybe I need to take out and do some hard braking, put some heat into the brakes? It's not quite time for winter tire changeover, and that is when I usually take apart the brakes to make sure everything is free-but since it's only been a year and 5k since the last time I did that, I'm somewhat dubious that anything has frozen up (apart from a piston perhaps).