Code PO422 rough idle, stalling

The most common cause for the P0422 trouble code is a malfunctioning catalytic converter. However, there are a many other issues that can result in the code (or that may cause the catalytic converter to malfunction), including the following:

Faulty oxygen sensor.
Malfunctioning coolant temperature sensor.
Faulty fuel pressure regulator.
Faulty manifold air pressure sensor.
Malfunctioning mass air flow sensor.
Contaminated engine oil.
Engine leaks upstream from the catalytic converter.
Engine is misfiring.
Loose or damaged wires and connectors.

I would suggest that you start checking all in the list above and re post for further assistance if required.

Unfortunately I cannot give you a suggested line off attack, probably do the least expensive checks first, start small and work up.

At that many miles, I would start with checking the catalytic converter. If it is not welded on (ie it can just be unbolted) I would drop it, take it for a ride, and see if it is better. If it is welded, then I would pull the O2 sensors and again take it for a ride. Yes, it will be noisy. But it is an easy way to check catalytic converter's performance.

P0174 is a code for a Mass air flow sensor and the P0300 is a random engine misfire, this may be triggered by the MAF code so look here first.

Not unknown to have a bad new item, just check that the electrical connection is sound and tight and there is no corrosion on the terminal pins.

Yeah it definitely wouldn't be the first time that a sensor from AutoZone was faulty. I'd probably probe the connector though to make sure that it was receiving power and jiggle it around to make sure that the connection wasn't weak. If the connection is ok, then return the sensor and get a new one. Good luck and keep us posted.