keep failing smog check due to high nox levels. replaced pcv valve, o2 sensor, catalytic converter.
Aug 20, 2008 at 9:37 AM
1999 Other Saturn Models high nox levels
1999 SATURN
IPRINGLE
- MEMBER
- 1 POST
Nox is exhaust temp which is controlled by the EGR valve. If the valve is vacuum operated, use a pump to open the EGR valve, the engine should stumble hard if not die, if it doesnt, the passages could be plugged. If the valve is electric, you will need the proper scan tool to make the valve open to see if the passages are clear or if the valve is bad
Aug 20, 2008 at 10:11 AM
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