OK, I am going to put in a new O2 sensor. The guy said there is a knock off for $60 or a Subie one for $100. Does anyone really know the difference? Recomendations please! Thanks.

 

It's for a 98 OBW

Check this site http://www.oxygensensors.com/ I belive there are 2 different sensors that will fit, most after markets have 3 wire hookups. If you can find a 4 wire which has the direct ground, I think you'd have a better off.

The front sensor is a three wire, the rear sensor is a four wire. You probably only need to replace the front sensor.

 

That site has good prices. I have been pleased with the O2 sensors I purchased from them.

There is one floating around on ebay, I think this might work (but u should confirm it. It is a several wire sensor, not a single wire.

 

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&category=33557&item=2462291183&sspagename=STRK%3AMEBWA%3AIT