[200q20v] Stumbling Problem

[Jeff.Bernstein at pneumaticscale.com]

Below is a description of a problem that I had a few weeks ago.  I found the
solution to this problem about a week later.  It ended up being a bad  Air
Mass Sensor.  I did not have a code stored for the Air Mass Sensor but
determined that this was a key part to determining the fuel mixture.  
I found that the best price for a new Air Mass Sensor is about $500 and a
used one is $350.  I called a friend that is a foreign car parts dealer and
he got me a rebuilt unit over night for about $200 with one year warranty.
He also can get rebuilt rear calipers for about $100 which is the best price
I have seen anywhere.  If anyone ever needs another source for parts let me
know and I'll forward you the info.
I have been having a stumbling problem when I accelerate the last few days
and have not been able to determine why. Every time it does this stumbling I
pull the code and it is always the same--2341 that is listed below. The car
has run fine for the last 170,000 miles until the other day on my way to
work when the stumbling started. It doesn't always do it though and it seems
to come and go. I have replaced the oxygen sensor, cap and rotor and the
ignition coil. I have also replaced the upper and lower inter-cooler hoses
just as preventive maintenance. Does anyone have any ideas on what to do
next or has anyone had a similar experience?
 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, 
Jeff Bernstein 
'91 200Q
'90 V8 Q
'91 Coupe Q