abs brakes rumble

While I'm going to be taking my RL in to the shop about this issue (about 90k miles on it), over the past month or so the car shudders a bit (not much noise) just feeling through the steering wheel an car. I'm wondering if anyone has seen this before or knows what might be going on. 2011...

My 2006 with 158k miles developed a problem five days ago that seemed at first to be a tread separation. Now I think it may be an ABS issue. Need your suggestions. I drive very long distances, and pull a utility trailer or a 19ft Airstream through mountains. I installed four new Michelin LTX...