[kerbyjonsonjr]

I have a 1996 9000 CS and from time to time my check engine light will come on and I got the code checked out and it says it's the oxygen sensor. I have also been getting about 6 or 7 miles per gallon less than I normally do so I think it's time I change them.
Is there anyway to tell whether it is the oxygen sensor that is before or after the catalytic converter or is it best to just change both of them? Does anybody have any experience with the universal ones that require splicing or is it worth the extra money to just get the ones that fit and plug right in? I've had good experience with http://www.thesaabsite.com/9000/9000fuelsystem.htm so I was just thinking of buying from them. It would cost me about $130 for both sensors from that site so it's not tooooo bad.
Also, is there any trick to getting these suckers out? I tried getting the one that is before the catalytic converter out and I couldn't even get the thing to budge. And lastly, is there an easier way to get at the place where the wires plug in or is reaching around and just feeling for it the best way? Thanks for any help!

 

[Jim Mesthene]

I've had good experience with http://www.thesaabsite.com/9000/9000fuelsystem.htm so I was just thinking of buying from them. It would cost me about $130 for both sensors from that site so it's not tooooo bad.

Generic substitutes are fine.
Swapping parts based on stored codes may not prove to be cost effective.

 

[Twinsen]

If your fuel economy has dropped suddenly, it's the upstream sensor, though the code should tell you which sensor. If the heater impedance of the generic sensor is much different from stock, the ECU will throw a code. It's happy at around 8 ohms.

Like you've discovered, the sensor in the cat is a headache. It's best left alone unless you know for sure that it has failed.

 

[Shan]

When my MAP sensor started to fail, the oxygen sensor code popped up intermittently. A week later, the MAP sensor died completely and the MAP sensor code appeared.

 

[jw.roberts]

if you know anyone with a scanner/code reader that will show live data watch each O2 sensor make sure the voltage is flipping above and below .5 as far as the sensor itself generic is fine. O2s are universal your paying for the wires and connector being ready to plug in. get a can of PBblaster soak em and let em sit for a while. if still can't break it loose try tightening a little then try to break it loose again just ve careful not to round it off. good luck and watch ur knuckles

 

[KevinC]

If you do need to change them, my experience: penetrating oil and special sockets do not work on the tough to get out ones, 2,000F torch does work.

 

[c900]

When the o2 sensor is working, it should output a varying DC voltage swinging between about 0.4 and 1.0 volts. Tracking down a replacement atm since I now have two cars that could need one (my 2.1 900 as well), and I'm hunting for a genuine Bosch or OEM Saab one.

Craig.