I threw an 0303 code a couple of weeks ago, and replaced the front left bank O2 sensor. The car has been running great. Today I got an 0503, which is the front right bank sensor. Should I simply replace it, or look for something else that might be causing a problem? The car ran much better after replacing the left bank O2 sensor, but I'm a little puzzled by why the right bank would also go out. Any thoughts?

 

I would throw o2 codes when the car was running rich, but I'm on 370cc injectors. You are either getting too much or too little fuel, check your injectors. An exhaust leak might also cause it to throw a code.

 

Thanks. There doesn't seem to be any new exhaust noise, but I'll dig around to see what I can find. Is there an easy way to test the injectors?

 

well, once one goes, they all start going.best to change all at once,although thats very costly.however it could be injectors as well.

 

Are there separate codes that will be thrown if it's the injectors, or is that something you just have to check manually?

 

Replace the o2 and be done with it.

 

Yup...it's worth the try and will eliminate the sensor if there's something else going on.