Wallace White wallacewhite at yahoo.com writes: <Is there a way to really know when to replace your <oxygen sensor? Go here: http://www.sjmautotechnik.com/injector.html#osens and http://www.sjmautotechnik.com/injector.html#o2test hth, chris miller, windham nh, c1j1miller at aol.com '91 200q20v http://members.aol.com/c1j1miller/