Any can point to the exact location of the Oxygen Sensor for 2004 GX470. Is it easy to replace? What about simply using higher octane and additional fuel injector cleaner, would that help?

 

Are you reading based on the Fault codes that this needs to be replaced or another reason. Maybe more detail would be better for the need of replacement.

 

yes, based on fault code. Tried reseting engine light, but came back on. Went to O'Reily auto part, read the code and said Oxygen Sensor Bank 1.

 

The O2 sensors are located towards on the Front Exhaust pipe ( Front Left & Front Right) (on the bend pipe). Ideally its better to replace both same time which are located on either side of the mandrel pipe towards the engine facing( below Once raised) . Ensure to disconnect Battery and do the job when the engine is cold. First disconnect the harness which the Old O2 sensors are attached to and use normal tools . And ensure to apply sufficient graphite grease which come along the pack on the threads of the New O2 sensors. Denso is the brand P/N is Super Class OE identical O2 sensor 234-4138. Costs 72/-a pc) here is the link. The job should not take max 30 mts ceeyaa
http://www.densoproducts.com/results...ctCategoryID=2