Toyota is recalling certain model year 2007-2011 Lexus GS350 vehicles manufactured June 19, 2006, through July 12, 2011; and model year 2006-2011 Lexus IS350 vehicles manufactured May 27, 2005, through July 13, 2011; and model year 2010-2011 Lexus IS350c vehicles manufactured November 25, 2009, through July 19, 2011. These vehicles, equipped with the 2GR-FSE engine, use bolts to secure the housing and sprocket of the Variable-Valve Timing (VVT) system gear assembly. These bolts could become loose due to abnormal impacts generated within the gear assembly immediately after a cold start-up.