hi guys need some help

long story cut short

car came very flat unresponssive i did some basic tests and sujested maf sensor customer who is always right said hed checked on the forun andd its definatley the o2 sensor i siad i had checked it and it was ok but he insisted so i changed 02 sensor and cat as sensor stripped out thread on its way out
Car still the same then i changed maf sensor car now revs fine and pulls well but its idle is up and down and you can see throttle moving as it does so
reset throttle body but still the same
if i unplug the new maf sensor idle becomes steady but as soon as i plug it back in its starts reving up and down again as does the voltage off the sensor from 0.7 to 1.3v

It ill idle around 1000 rpm but as you let it decrease it starts reving up and down

i have read some where about reseting adaptions but am not sure how to do this as it asks for a number between 000 and 250 not sure how to do this
or is it just a faulty sensor

help please brian