If there are no other problems and the vehicle is failing the NOX emissions test, it's probably running too lean. Check the EGR valve, fuel pressure and the Oxygen sensor.
Performance may be okay but you will probably fail an emissions test.
After hundreds of thousands of rotations, the bearings in the impeller will fail.
Yes, that is a possibility. A sensor can fail in many ways.
Depends on the year, which you fail to list. It will not be good no matter what year.
The blower motor is beginning to fail. Bearings, bushings, or brushes are probably worn.
Yes if it is emissions related.
That will cause you to fail an emissions inspection. Anything which triggers the CEL will, because everything which triggers it will adversely impact the emissions system on that vehicle.
The front axle is not disengaged OR the front u-joints are starting to fail.
A dirty fuel filter could force a lean condition causing the check engine light to iluminate. In which case the vehicle would fail an emissions test.
you will fail the emissions test.
The vehicle will fail an emissions test.
No, but you will fail an emissions test.