Any smog experts out there?

Sterling said

NOX is usually EGR related, the egr valve could be working properly but if the ports are carboned up it will not flow enough to work correctly

Click to expand...

I agree and that's the first thing I checked. I found a strong signal to the EGR valve when I rev the engine, and if I apply vacuum to the valve at idle, it opens and makes the engine die. That shows it works fine to me.....