Toyota Repair: High NOx readings, toyota camry xle, combustion temperatures

Question
I unfortunatley live in a community that requires emmissions test.  I can not get the NOx reading low enough to pass.  I have replaced the cat, O2 sensors, cleaned and made sure the EGR valve is working properly.  I have checked the EGR vacumn modulator valve and seem to work correctly; however I am not sure of the test.  The one thing the is different from the last the car pass emmisions is a new radiator and the engine runs much cooler now.  By the way it is a 1992 Toyota Camry XLE V-6 3.0 engine.  Not from California.  A/C Auto.  All other emmissions are well within spec.
Your Help would be appreciated

David Spitler
Milwaukee, WI

matzen@execpc.coN

Answer
High NOx readings are directly related to combustion chamber temperatures, if they are too high, the nox gas emissions will be high, this is the reason EGR systems were put on engines, even though your engine seems to run nice and cool the internal combustion temperatures my be too high, since all the other exhaust emissions are within limits the only thing left is the egr system, make sure that the modulator valve is good, remove it and see if air passes through from the bottom port, if it does the valve is no good, if this checks ok have the system tested by a repair shop.