Hey all. I have a 2005 Nissan Pathfinder 4x4. We recently moved to Maryland for a job and found out they do vehicle inspections here. My Pathfinder has had the engine light on for some time and the dealership gave us information that the light is either a catalytic converter OR O2 Sensors (4 total). I replaced the DS Front one and the light popped back on so recently I went on EBAY and bought all for for a heck of a lot cheaper and NEW. In the time since, my oil pressure gauge is pegged on HIGH also, so for $17 I went on EBAY and bought a new one to do it all at once on a rack. It is said to disconnect the battery and remove all O2 sensors and replace. You may also clean them using a cup of gas covering them over night but I will opt to replace to be safe. Good Luck and UGH!