How can I lower my High Speed Nox (ppm)? on 1994 Honda Civic

I failed the inspection for my nox (ppm) on my High Speed Emissions test. The standard is 1240 and my result was 1267.

by in Deer Park, TX on November 06, 2012
3 answers 2 comments
ANSWER by on November 06, 2012
ck egr passages for blockage of carbon or timing can be retarded or poss o2 sensor
ANSWER by on November 06, 2012
Globalhelpers suggestion first!! EGR SYSTEM function is very important. Next would be timing as he mentioned , and then be sure the cooling system is in good shape. Last , if high miles (by age I'm assuming it is) maybe a top engine cleaner -get carbon build-up off pistons -lower comp. lower combustion temp=lower Nox.
COMMENT by on November 06, 2012
well said zip man
COMMENT by on November 06, 2012
Thank you.......:) ......never mind.
ANSWER by on November 06, 2012
Check EGR, and Carbon build-up