1T42T (aka ZZ CETT)

2 Fault codes:
17608 - N249 - mechanical malfunction intermittent
16804 Catalyst system: Bank 1: Efficienct below threshold

These are similar to what I saw when I had a bad MAF. But I got it replaced only about 2K miles ago. The car is running well, though.
Do I have another bad MAF, or is the N249 really acting up? (I have a stock MAF with no screens and a TTDA -other things, too, but
this is all that's probably relevant -OK, Forge FMIC, too.)

Thanks,

scot