My local subaru dealer told me I needed a new MAF and o2 sensor on my 2002 WRX. I replaced the o2 sensor yesterday myself and cleaned the MAF. Car is running much better but still seems to hesitate a smidge while accelerating.
This guy says MAF can be tested with a multimeter.
How to check and change a Mass Air Flow Sensor for a 1999 Subaru Forester
Anyone have any more info on how to do this? Mine is 5 pins. No clue what ground is on the sensor. I'd love to be able to determine if this is the problem before buying a part that is that expensive and non-returnable.