Well it appears my front O2 sensor is dead or very close to it. It looks like the options for replacement are expensive Subaru sensor, or universal Bosch. So my question, does anyone know if the plug on the front and rear O2 sensors are the same?

On a somewhat related note, does anyone know if you can get a misfire (or 3 :eek: ) from running to rich? I had my e-manage set up to run a fairly rich map, but then with the O2 throwing a CEL I think its running super rick. Could my 3 misfires (1,2, and 4) be related to the O2 sensor?

The conectors for the front and rear sensors are not the same. The front sensor is a wide band and the ECU uses it for closed loop fuel control. The rear is just a narrow band and is only used for emisions control.
Running to rich will difinatly cause misfires.

You sure about the front being wideband? I know the WRX is, but I'm not sure sure about the GC8's. The ECU pinout I have shows the front sensor as putting out 0-1v.

Anyways, I went to NAPA this morning and they didn't have anything. No stock replacement and no universal to solder in. Am I stuck getting one from the dealer?

www.subaruparts.com has them for about $30 less than the dealer.

Yeah I was hoping to get it before my dyno time on Saturday though. I'm getting one from subaruxtras.com for a great price, so I should be set (and it will be here tomorow hopefully)

yes, the front on a GM6/GC8 is a wideband sensor.

the front O2 sensor heater circuit is 1V
the sensing circuit is 5V
look here

Slim chance, but does the WRX front O2 sensor work on an RS?

Originally posted by lotusTT
Yeah I was hoping to get it before my dyno time on Saturday though. I'm getting one from subaruxtras.com for a great price, so I should be set (and it will be here tomorow hopefully)

I'm in need of an O2 sensor myself. I checked at subaruxtras.com and couldn't find one for my GC8. Is it not listed in an obvious place?

Send them a PM or call and talk to Mike. $68 plus a couple for shipping. Subaruparts.com wants $100.