New OEM Nissan Upstream (Front) Oxygen Sensor for all '03 - '04 Nissan 350Z's and Infiniti G35's / FX35's.
2005+ Front oxygen sensors can be found HERE.
Installed before the catalytic converters on the exhaust manifold, these sensors often prove to be extremely difficult to remove without destoying the threads when installing an aftermarket set of headers or forced induction setup. These sensors are also referred to as an "Air-Fuel Ratio Sensor" by Nissan.
Sold individually, one sensor will fit either the Left or Right side of the vehicle.
Z1 Motorsports recommends the usage of an anti-seize compound on the threads of the oxygen sensor to make future servicing much easier.
*NOTE* If purchasing for a 2004 model, it is important to know that some late production 2004 models were equipped with '05+ 'Wideband' type oxygen sensors. It is highly recommended that prior to purchasing you first check the pigtail on your oxygen sensor to verify sensor type on your car using the image below. You can also submit VIN numbers in the product questions below for verification. If you have the wideband type indicated by the plug on the left in the image below, you will need to purchase '05+ Oxygen Sensors found HERE.