[200q20v] ECU Code 2341. Now What?

[Frank Stadmeyer]

My '91 200Q has been flashing the check engine light at me, mostly in 
traffic when the engine temperature goes up but occasionally on start up. I 
pulled the codes and got 2341 only.  Here's what Scott's site says about 
that code:

"2341
         Oxygen Sensor Control Limit exceeded,
         fuel pressure too low or too high, intake or exhaust leak, 
defective ignition system component,
         intake air leak after air mass sensor, O2 sensor is faulty
         Symptom: CO before catalyst is below 0.3% or greater than 1.0%,
         Extremely lean or overly rich exhaust, Spark Plug fouling,"

The car seems to run fine.  Pulls full boost and idles well.  The fuel 
mileage might be a little low but with the cold weather it's hard to 
tell.  I did change the O2 sensor once before but it was a while ago and 
the car has 175k mi. now The sensor probably has somewhere between 30 and 
60K on it (maybe more).

Any suggestions?  Change the O2 sensor?   I'm due for an emissions test 
this month,  should I just let them test it for me?

TIA

Frank Stadmeyer