I recently failed my state emissions test.  I drive a 91 Toyota Camry
with 190k miles.  Here are my results

                                 High Speed (25mph)

Pollutant                Standard               Current
Reading            Result

HC (ppm)                  123
26                         Pass
CO (%)                      .69                          .
13                         Pass
CO2 (% )                                                 14.6
O2 (%)                                                     19.7
NOx (ppm)                 878
1093                       Fail

                                 Low Speed (15 mph)

HC (ppm)                  128
127                        Pass
CO (%)                      ,71                           .
31                        Pass
CO2 (%)                                                   14.4
O2 (%)                                                      20.4
NOx (ppm)                970
947                        Pass

As you can see from the results, I failed on the NOx and was very
close to failing on HC at low speeds.  What particularly puzzled me
was the high O2 readings.   I looked at the results of my tests for
the past 5 years and I have never had an O2 reading over 1%.   What is
going on here?   Was it a malfunction of the test??

I should also mention that before taking the test I did all of the
usual things to prepare for the test:

1. spark plugs have less than 2 k miles on them
2. changed oil and filter
3. changed air filter
4. checked spark plug wires and distributor cap for leaks
5. checked egr valve for proper functioning
6. checked compression. 170 - 175 psi on all cylinders.
7. drove the car for 15 minutes on freeway.  Left the car idling
before test.

I would appreciate a few thoughts about this problem.  Thanks.