Anybody know if there is any drivability, performance, or acceleration problems when your o2 sensor is bad. I am getting ecu codes of 0304 and 0707 ( knock sensor and rear o2 sensor) . I replaced o2 sensor in '98. Do I replace both or the knock sensor only, because I have performance lag.

thanks.

 

If your getting both codes, do the o2 sensor first, then reset your ecu.

The KS code is usually tripped by a bad o2 sensor. They refer to that as a ghost code.

 

yeah, but does the o2 sensor lower driving performance?

 

you also might try removing the O2 sensor and cleaning it off with a bit of alcohol. let it dry and reinstall.

 

No, the sensor indicated by 0707 will not affect mileage, performance, or drivability. It is merely there to monitor catalytic converter health.

 

my rear heated 02 sensor is fried (0305) and it sures as hell HURTS your performance! my friend has a spec-v that i usually take by 3-4 cars to 100 but right now since i havent replaced the 02 sensor his car walks ALL over me. its pathetic.

 

i agree

 

Sorry man, 0305 would be your EGR Temp Sensor. 0707 is the Rear Heated O2 sensor. No wonder your car runs like crap. You better get the EGR Temp Sensor fixed.

I say again, a bad Rear Heated O2 sensor does nothing for performance, its just a monitoring sensor. Now, if one of the two sensors for each bank of cylinders fries, then you'll have fuel economy and power issues, but the car will still be driveable.

 

by the way, I went to the ECU decoder page, and just for Sh*ts and Giggles, entered in 0503, and it turned out to be a "Front Right Heated O2 sensor". This is your problem, not the Rear Heated O2 sensor. Makes sense now. Here's the decoder page for quick reference, I'm pretty sure you know how to get to it otherwise.

http://vbxmaxima.8m.com/ecudecoder.html

 

The fact that you have noticed a drop in performance along with the 0304 code is a clear and positive indication that your knock sensor needs replacement. The rear heated O2 sensor will not affect performance, as others have stated.

 

actually thats what i meant it is the 02 sensor..... my bad.



EDIT: now that i think about it....i guess it "could" have been the 0305.... what exactly does that sensor do? i cant go check my codes again because my car is in the shop. it keeps blowing ignition fuses for some reason....

 

thanks for all the info!

 

This guy's got my vote

FLO_BOY

 

My performance was the same with the rear heated o2 sensor..i just had the stupid CEL light on.

 

is there a CEL code for a bad cat or would you get a code for the downstream O2? just something this thread made me think.