You're NOx readings appear to be within spec, so your EGR system is probably working.

Your HC and CO readings are what is too high.

Likely a catalytic converter gone bad.


1995 Trooper LS auto 3.2 DOHC /w SOHC intake
1989 Trooper 2.6 auto
1989 I-Mark RS DOHC 1.6
1991 Stylus XS DOHC 1.8