Miller lifted the Bahamas to a time of 2:56.72, .33 seconds better than the U.S.
Trinidad and Tobago took third.
The South African team, anchored by double amputee "Blade Runner" Oscar Pistorius, fell behind well before Pistorius received the baton and finished last.
Taylor, a 400-meter hurdler, was thrust into the lineup after a flurry of injuries hit the Americans. Lashawn Merritt and Jeremy Wariner both pulled out before the preliminaries, where Manteo Mitchell ran the last 200 meters of the opening lap with a broken left fibula.