There is a test you can do on the air flow meter to see if it is working or
not.  It is in the manual.  You pinch the air hose on the top of the motor
that attaches to the rubber duct that is connected the air meter.  When the
motor is cold the rpms should drop.  When the motor warms up you pinch the
hose again and the rpm should not drop.  If you need more info I can bring the
manual in and type the directions out for you.  Let me know what you find out.
I have a good airflow meter that I would let go for $150.
Ken Wilford
John 3:16