Your 1992 Jeep Cherokee is not equipped with an EGR valve or EGR system.
Normally the EGR valve (Exhaust Gas Recirculation) system controls and
lowers NOx. On your Jeep Cherokee, NO is controlled completely by the
air/fuel mixture and the Catalytic Converter (CAT).
Assuming your 1992 Jeep Cherokee's air/fuel mixture is ok (this should be
indicated by normal CO emissions - check your VIR report) we'd recommend
suspecting the CAT. If the CAT is the problem the only thing you can do to
get your Jeep Cherokee lower NO by 11 ppm and to pass the smog check is the
get the CAT replaced. You can find an aftermarket CAT from a muffler repair
shop or smog check repair center for a low price.
To check the condition of your Jeep's Catalytic Converter a smog check
repair station will have to perform a CAT intrusive test. They will need to
take an exhaust sample from before the CAT and after the CAT, and compare
the results. They will then find out if in fact your Cherokee's CAT is
damaged and needs to be changed.
