It might not be that the MAF can't read that much air but that the air it's trying to read doesn't flow correctly into the MAF. That the air flow is disturbed. I've read that this is a problem with some aftermarket cold air ducts.
wut he said
You can try re-clocking the MAF with your CAI but honestly... There really isn't a better CAI for a Fox than the stock one with the silencer removed... Unless you're running some 80-90mm inlet tract.