Recent emission test revealed the following results for my 87GL 2wd.

Can any of you list members suggest what needs to be fixed?
So far I have replaced plugs, cap/rotor, air filter and oil.
But I have a suspicion the catalytic converter or O2 sensor may be bad.

________Limit____Reading___Result___
HC ppm  122        162      FAIL
CO%    0.87       0.73      PASS
NO ppm 1365       2143      FAIL
               RPM          2037     VALID
            DILUTION                 VALID

VISIBLE SMOKE INSPECTION: PASS

Ken Madsen, Toronto, Ontario
87GL (Flash)
87 Golf Diesel (Smokey)
95 Jetta GLX (Black Beauty)