Just failed emissions, again! I have a hunch its an O2 sensor but here are my readings, hopefully someone can help...

HC 0.5335 / 0.5000
CO 0.0486 / 9.3200
NOx 1.1606 / 1.2400

So it looks like im running lean, CO is suuuper low. HC Failed, NOx was close to failing as well Car was well warmed up for the test.

I just put MAC's on a few weeks ago (i was failing before them too) and put an almost new GM Cat on. Changed the plugs as well while in there. EGR was swapped out maybe 3 years ago too.

 

did you have the ecm retuned for 30# injectors? if not, I would start there.
did you remove the air pump?

 

Yes Air pump has been removed, and the cars definatly been tuned for the SVO 30#'s. The car was warmed up for 20ish minutes and sat idling at hte test center for another 20 minutes or so. It was definatly way warm.