2002 Sienna XLE
Friends, what should I do, my '94 Corolla DX 1.8L with 300K+ from Maryland failed CO only in California. Recently I put a new Catalytic converter, Timing set, radiator, water pump, thermostat, some new vacuum hoses and distributor. After the CO failed I put a new OS sensor and coolant temperature sensor and OH! some Castrol stuff to make the oil thicker then retested only to fail Nox only. Am I wrong to feel suspicious that the technician stuck a wood dutch shoe under my hood? This engine does not have an EGR.