the MAF can actually be 'refurbed' pretty easily without changing the calibration. If youi take the cover off, you will see a wiper arm and a carbon track it follows. The carbon track can get worn in spots -- if you carefully mark the arm/pivot position, loosen the arm allen holding setscrewm and simply push the arm down a tiny bit, (without changing the rotational relationship to the air flap) you will find it moves the contact a bit outward-- toward fresh virgin carbon. 1mm is enough.
At least I;ve done that twice on 24V AFM and it worked great.
74 GTV with 10548's and Ingram pump
71 Spider 1750 BOMBER ; 1995 LS 78K tight fast car