Chevrolet Repair: emissions, nox emissions, chevy 1500

Question
I have a '94 Chevy 1500 4.3L V6 w/auto trans. My NOX gas level during emissions testing was better than 1700ppm. I changed the EGR valve and vaccum line. I have it down to about 1050ppm. What can I do to lower this NOX level further? TX requires no more than 990ppm. The other gas levels are good.

Answer
Hi Jimmy,
Nox is formed by high combustion chamber temperature. Getting that temp down should help. That is what the egr valve does.
Go to Google.com, and search for nox, and check some of the links that come up.
Or try ask jeeves.com, and ask how to reduce nox emissions.
Good luck,
Van