The IMPOSSIBLE Mass Air Flow Sensor problem??

I recently purchased a used 2005 Hyundai Sonata V6 from a friend. He recently replaced 2 belts, and the car had a P0340 code. I had a shop fix them, and now I have a P0171 and P0174 code. The shop said it was the Mass Air Flow sensor (MAF), so I swapped it with an aftermarket from autozone. The CEL came back on, and the shop told me that Hyundai's don't support a lot of after market parts. So I return the replacement MAF, and the guy at autozone confirms this happens on Hyundai's and Infinity's.

So I find another MAF from a 2005 Hyundai Sonata V6 online, and swap it, and the light comes back on. The weird thing is that I had to drive 200 miles for the light to come on. All the other fixes I tried, I only had to drive 25-50 miles. I'm trying to get it inspected, and I kept failing because the O2 sensor hadn't finished it's cycle.

Does anyone know that could possibly be the problem??
And why did the MAF light come on AFTER the timing belts got fixed??