I have a 96 legacy 2.2L with the check engine light on. It usually will stay off for a couple days then come on and the code will say bank 1 below threshold, which I assumed to be 02 sensor not working correctly. I replaced it but it came on the same as before. When I replaced it there was 1 black wire and 2 white wires that I couldn't tell the difference between. Could I have missed that one and hooked up the 2 whites backwards? Also how can a person test the o2 sensor for working correctly and is the a easier to get to connector where I can test it.

Also I have an intermittent rough idle when warming up. Runs fine right at start up (I'm assuming cold start valve is working) but after a few seconds it idles around 300-400rpm making the car shake a little. Once warm it idles closer to 600-800 and feels better. I've heard it could be fuel pressure regulator. Is there a way to test it. I have a diagnostic fuel pressure gauge, so if the needle is sticky will the pressure read different at idle cold vs warm?

If there is a loose body ground could it cause an electrical discharge ( like static shock) when getting out of the car and closing the door?

Thanks for your help guys!

Nate

nate, your vehicle has two O2 sensors. which one did you replace, the front one i assume?

 

definitely check your wiring. to your question "could i have switched wires" i will say "yes".

 

O2 sensors are Subaru only preferred items by some, but based on some details i am not thinking that is your issue here.

 

as for the idling problem, i would clean the idle control mechanism. they get clogged and sticky with age/time. very common and easy to fix. just clean it out. though i haven't done it to an EJ vehicle yet so i'm not sure where it is.