cbscooby

iTrader: (1)

can anyone tell me what are the tell tell signs that the maf is on its way out,

myblackwrx

iTrader: (1)

Unplugging it and the car doesn't stall.
Car may start to misfire when on boost.

FFForester

iTrader: (5)

Mine started off as slight hesitance when accelerating, then got worse to the point where hardly any power above 2.5k revs

Splitpin

No, ignore this advice, it's bad. If you try it a couple of things could happen: Your car could stall with a sensor that is knackered, or you could damage a good one.

Unfortunately it's very difficult to diagnose a failing airflow sensor accurately without actually diagnosing the car or using some sort of external monitor. Hunting idle is one possible symptom, as would the car feeling faster or more powerful (due to running leaner), although this can be difficult to detect if the sensor deterioration is subtle or gradual.

In either event though there are other potential causes so the only way to be certain is to directly check the sensor's output with a diagnostic tool, or to indirectly it by using devices that will monitor the mixture (or changes in it).

Short of plugging a select monitor (or similar) in and checking the sensor output on the road, the best "indirect" way to diagnose a failure would be via an AFR meter or a knock monitor. The AFR meter will show the car running leaner (or the mixture becoming inconsistent) while a knock monitor will get quite busy.