If your Acura SLX Air Flow Meter keeps failing the issue is most likely to much oil on a Acura performance air filter, or to much blow by from the SLX engine.
If your Acura SLX failed the emissions test due to high NOX, the EGR Valve is most likely the issue. If your Acura is running rough or has poor fuel mileage, replace the SLX EGR Valve and gasket.
The Acura SLX 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 Acura SLX diagnosics codes for proper replacement of the O2 Sensor.