[cheshired5]

I had a MAF fault with low and erratic figures so needed to check if there really was reduced airflow or if the sensor was duff and unable to react to airflow changes.

I removed the MAF from the air box but left it plugged in to get readings and simply blew on it.
It produced the same duff readings but blowing on the working replacement gave the expected rise and fall in airflow readings.

Simple but effective MAF sensor troubleshooting.