If your Honda Passport Air Flow Meter keeps failing the issue is most likely to much oil on a Honda performance air filter, or to much blow by from the Passport engine.
Use only Honda OE quality replacement Catalytic Converters to keek your Honda Passport in the best running condition. DriveWire sells only California legal Passport OBD-II Converters.
If your Honda Passport failed the emissions test due to high NOX, the EGR Valve is most likely the issue. If your Honda is running rough or has poor fuel mileage, replace the Passport EGR Valve and gasket.
The Honda Passport Oxygen sensor is a critical part of the emmision control system and should be replaced as soon as it fails. Make sure to check the Honda Passport diagnosics codes for proper replacement of the O2 Sensor.