After an hour on the road traveling a highway speeds (50-70 MPH), the car jerks like it hit something (it did not) and the cruise control disengages and will not reengage for about 10 minutes. (This happened 3 separate times within a week.) Could be the abs engaging which simulates pressing on the brake but not sure. Pretty scary shake when not expecting it. This did not occur without the cruise control engaged? Any ideas?