Oxygen Sensor (After Cat), 1997-1999 Wrangler (4.0L), 1996-2000 Cherokee (2.5L and 4.0L), 1996-1998 Grand Cherokee (4.0L). Has your Jeep failed an emission inspection? Do you have a Check Engine light on? Over time oxygen sensors will go bad. They are usually easy to replace and will keep you on the road legally. Get high quality oxygen sensors from Omix-ADA to keep your Jeep legal. It will run better too