(1) new OEM Bosch Oxygen sensor for a 1990+ Nissan 300zx.
This is the primary O2 sensor that fits both left and right sides of the exhaust on all NA and TT Z32 models. A Z32 requires (2) of these. 1996 US models also have a pair secondary O2 sensors behind the catalytic converters.
Replacing non functioning or lazy oxygen sensors will pay for itself in wasted fuel.