Hello Everyone,

1998 Trooper 3.5L...is failing smog, (High NO) Scanned the computer and there is no DTCs detected. Checked the I/Ms and all systems says it is ready.
Check Engine is not on, all fuses are ok, I checked them individually on the fuse box in the engine bay as well as the fuse box on the bottom left on the driver''s side.

I''m removed the EGR and cleaned it to rid of the carbon buildup. I am guessing that the EGR could have failed mechanically. Is there a way to see if the valve on the EGR work?

Could it be the O2 sensor has failed?

Or the Catalytic converters gone bad?

Any idea what else maybe causing this?

Any suggestion is appreciated.

Thanks.[img]smileys/smiley19.gif[/img]