After my engine would warm up approx 2 min, the air/fuel would show the engine leaning out. If you turn the car off then restart after 5 seconds it would start rich, as normal, the go to normal operation. Sometimes you may have to do this twice. I changed the O2 sensor with a Bosch universial. Now it runs rich until you get 2500-3000 @ 55+ then it runs in the normal range amber/green on the air/fuel. I have been told that OEM is the only sensor to use, that universal sensors are not accurate. I removed a Denso sensor.
94 JDM GSR
JR supercharger
Thanks.

 

I'm sorry, but what exactly is the question here? "is it the o2 sensor's fault?"

(also might wanna delete your duplicate thread...or have a mod do it)