AFM is your Air Flow Meter(a.k.a. MAF-Mass Airflow Meter).
That is that silver box with an electronic plug where you CAI(Cold Air Intake) connects to.
In many cases, a CAI filter is much less dense in filter material, and allows not only air but also minute dirt particles as well. And if yours is the kind that uses an oil recharge every so often, the chances of contaminating your AFM/MAF is even greater.
For starters, you can take of the air filter, get some airflow sensor cleaner(regular brake cleaner will do), and clean it as best u can. and then reinstall.
Pay close attention also to the electric connector to the AFM, many times, the connector pops loose.