Christopher
NAXJA Forum User
- Location
- Bakersfield, CA
What causes a vehicle to fail NOX. Just went in for smog & everything passed fine except for the 25mph NOX. Any ideas what causes this. I already did new air filter, oil & filter change, new plugs, new cap & rotor. Could it be EGR valve or O2 sensor. Any help apprecciated. Thx.