• Tiny
  • jjdaz
  • Pontiac Grand Am

I have a 1989 pontiac grand am with a quad 4 200'000+ miles auto transmission. Have replaced spark plugs air filter run fuel system cleaners as well as garunteed pass smog test additives. It has come a long way however not quite far enough. Initially failing all emmisions badly, I am now ok on carbon monoxide bot slightly high on HC's and NOX. Approx.15 over on each icannot find any way to affect these readings as there are no adjustments known to me please help

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have the same problem?
Friday, February 9th, 2007 AT 6:50 AM

1 Reply

  • Tiny
  • mmprince3000
  • Member

I would check the CAT convertor and scan the O2 sensor to see if it is running rich. A rich engine will kill a CAT in no time.

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Friday, February 9th, 2007 AT 9:25 AM

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