I have replaced tires this helped, replaced pads and rotors ac delco ceramic pads and oreillys auto parts rotors. I get a vibration at highway speeds and it will be noticeable then go away then it'll return. When I have the vibration I can be doing 70-75mph not let off the gas but lightly press the brake pedal the vibration will stop. The car had a brake booster and master cylinder replaced under recall. I'm running out of ideas . Could it be a defective set of rotors? The calipers feel like they compressed smoothly I'm leaving for Kentucky in two days and would love to get in resolved. Thanks everyone