Shaun Suisham's third field goal of the game gave the Steelers a 16-13 overtime win over the Chiefs.  The kick was set up by Lawrence Timmons' interception on the first possession of the extra frame.  Byron Leftwich replaced Pittsburgh quarterback Ben Roethlisberger, who suffered a shoulder injury.  Leftwich threw for 73 yards in leading the offense.  Heath Miller led the way with four catches for 47 yards as the Steelers moved to 6-and-3.  Jamaal Charles had 23 carries for 100 yards and a touchdown for Kansas City.  Matt Cassel threw for 154 yards with the costly overtime pick.  The Chiefs had a 10-0 lead early in the second quarter, which was the first time they've led a game in regulation this season.  KC fell to 1-and-8 with the loss.