[Lowcountry idn]

Normally I would say P0420 is cats, but your have a MAF sensor error also and your fuel trims are super high.

Clean Your MAF sensor and do the ECU relearn. Also, check the two flex hoses on the air intake - there known to crack which would give you a huge vacuum leak.

If that doesn't correct your fuel trims - replace your MAF sensor

 

[Lowcountry idn]

I have already tried cleaning and replaced the MAF. I have also checked for leaks doing the spray test. O2 sensors are new as well, but I've heard of them being faulty off the get go. My main concern was the volatility in the B1 O2 downstream. I seems a bit up and down. B2 O2 downstream is gradual like I'd expect. What should I be seeing in the air/fuel ratios?

OK, so I see those are actual Air/fuel ratio's - I thought those were your trims as I am used to seeing that as a lambda value where perfect is 1.0. However A/F ratio perfect at 14.7:1 so yours do seem pretty good.

I would double check your long term fuel trims if your reader can - they should be approximately +/- 5%. If they are, then its likely a cat.

But I still don't know why your getting a MAF sensor code? I would figure that out before buying cats. what brand MAF sensor did you use? Was it the same with the old one?