High Nitrous Oxide on emissions testing

[DMC6453]

Hi,

When I took my 98 corolla for emissions testing in california 4 years ago the Nitrous oxide was a bit high. When I took the car two years ago for emissions the NO was at the maximum allowable limit. I am worried when I take the car to emissions again it will fail. What is the most likely culprit? Some friends mentioned the EGR valve may be bad but I don't see that the 98 C9orolla has an EGR valve on parts sites. Please advise. the car does run and drive well with no problems and it has 187K miles. Don't know if I will need a new PCV valve or not

-Chris

[AlaricD]

Originally Posted by DMC6453

Hi,

When I took my 98 corolla for emissions testing in california 4 years ago the Nitrous oxide was a bit high. When I took the car two years ago for emissions the NO was at the maximum allowable limit.

Nitrous oxide is N2O.

You must have had high NOx (NO and NO2) emissions. This may be caused in part by a too-lean fuel mixture.

The PCV valve can usually be cleaned with carb or throttle body cleaner--if it rattles when you shake it it's probably just fine for the most part, anyway.