93' SR w/ 180,000km

Failed Nox

NO ppm limit: 557
NO ppm reading: 696


I know my timming could be a little off, I adjusted it a long time ago... but other then that I'm not sure. How can you tell if the EGR needs to be replaced? or the cat?

I passed 2 years ago with no problems

 

Before you go do anything else, just pick up a bottle of RXP and poor it in your tank. Run it on the highway for about an hour so that it gets good and hot, and take it in for your free second try.

 

If you fail NOX it's often a sign your EGR isn't working properly. You can try cleaning it out with some carb cleaner or something. That made me pass, barely. Or get a new cat!