Check engine came on few days ago. I done about 10 on/off cycles before reaching the car was. All's fine once I got to work. After I left, 5 mile after the check engine light came on. Checked it with the OBD2 scanned and detected the primary and secondary 02 sensor malfunctions. I erased the codes and it hasn't returned yet. No change in performance either. I'm driving a D16ya SOHC vtec

 

i think u forgat to write the question that u want to ask!!

 

Should I change the O2 sensor(s) or not?

 

What r the codes u got

 

From a OBD2 scanner P0138 & P0136 not oem honda scanner. The only differnce I feel in performance is when I get on the highway, after a 55 mph I feel a little more oomph out of the car.

 

your two o2 sensors are placed in front and behind the catalytic converter. The first one monitors how much hc's, co's, and o2's are coming directly out of the engine. The second one monitors the catalytic converters performance by reading for the same thing the first one is reading. With that information sent up to the ecu, check engine lights will usually come on. Because of the codes that came up, it is more than likely your o2 sensors. Your first o2 sensors detect what the fuel mixture is in the engine,by sensing o2. It then sends that information to the ECU, who changes the fuel mixture by grounding the injectors open longer or shorter. That is probably why you feel a difference after 55mph. At highway speeds, you car needs less fuel to run because of the increase in air flow. So more than likely your running a little richer than before. hth

 

So the question still remains, do I replace the O2 sensors or not. Is there a risk of clogging up the cat? I like the benefits I have now. better fuel economy. easily can stretch my tank another 75 miles or so. Tanked last night 355 miles and tin can not on yet. Only put in 10 gallons!! But if the cat gets blocked worse things happen.