I have changed all 3 or my 02 sensors and the car runs incredibly smoother and with better pickup etc..

I am still getting code 27 however, tried to reset ecu 4 times now and did not work.

There is only 3 02 sensors on this car correct?

1994 GS300 (w/cali emissions)

 

mass air flow, throttle response and the o2 sensor on the exhaust .