1999 Honda Civic 02 sensor check engine light

make certain you replaced the correct o2 sensor, the catalytic converter may be at fault here and not the o2 sensor itself.

should i replace the second 02 sensor the one by the catilatic convertor and see what happens failed drive test fuel mixture to rich obd11 code reader gave code p0135 then fixed it then got code p0131 so now i will replace second 02 sensor and see what happens could the obd2 code be not perfect ie the other sensor is broken

oxygen sensors are supposed to be replaced on a regular basis so it wouldn't hurt to replace the other one. be sure to erase the trouble codes after replacing it because the codes will not reset themselves.

so it failed the drive clean test in ontario at idle the gas was too rich

I will replace the second 02 sensor and erase the codes and see if the check engine light comes back on thnx

can i read my codes if i hook up loop to ecu wire in passnger seat and count how many times the check engine light flashes on 199 honda ciciv or do i need a code reader

if so which one do you recomned i am not a mechanic justa city worker

i would suggest taking car to a local auto part store after the sensor is replaced. most local auto part stores will hook up their scan tool to your vehicle and scan / erase codes free of charge.