My friend failed her auto emisions because her NOx is too high.
She has a 1994 BMW, 2-door, non-sports car, that she bought used. She's not rich at all, and the potential cost of this repair is troublesome after a new transmission less than a year ago.
What are some likely or low-cost things that might be wrong. The dealer had told her she might need a catalytic converter but that is ?? 3000 ?? dollars, or at least a lot.
Would you try replacing the O2 sensor without any code that pointed to it? Sensors can give bad readings even though the reading is within the limits annd doesn't set a code, right?
She's had plugs, cap, rotor, and wires done.
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