Engine Type is 3S-FSE
Did a diagnostic scan and got this problem code - P0135 - Oxygen Sensor Heater Circuit - Bank 1 Sensor 1.
It looks like I need another oxygen sensor.
I *think* the part number is #89465-44040 (from some quick google online) but I shall check physically.
The guys who did it say it should cost about 11k for a new one.
Effects of a faulty oxygen sensor apparently include poor fuel economy, so this should make things better :).