I just had my 91 Toyota Camry Le inspected for emissions.  It passed
everything but NOx.  I had the following readings

                    High Speed Test        Low Speed Test

          Standard         Current             Standard      Current

HC    123             26           128            127
CO (%)   .69                .13                     .71            .31
C02(%)                       14.6                                 14.4
O2 (%)                        19.7                                20.4
NOx       878               1093                  970          947

The part that I am especially puzzled about is the very high O2
readings.  In my test of last year, I had readings in the .5% range.
How in the world can I get a reading of 20% or more?  In fact, isn't
the atmospheric % of O2 in the range of 20%?   Is it possible that I
had a reading which reflects only that of atmospheric O2?

I would appreciate opinions on what is going on.

Thanks,  Al