P0172 and P0420 - Unmetered Air?

Hi-

2007 PRIUS with about 143000 Miles. I have been consistently getting P0172 and P0420 codes.

My issues started with random misfires Cylinder 3 and 4 and car running very rough- Car was obviously running rich and may have soured the cat??

After reading through multiple posts here (thanks Priuschat!) and understanding maintenance intervals- I replaced the following in the last 300miles

1. Fuel Injectors(made mistake and ordered reman ones)
2. Spark Plugs
3. MAF sensor
4. Upstream and Downstream 02 sensors


Now, the idle is better but still misfires (Shaking engine)- no misfire codes through only the P0172 code and then P0420- I am using Car Scanner Pro and a Bluetooth OBD2 Connector-

What are some of the steps to figure out where "unmetered air" is getting into the engine?


******When I was changing spark plugs - I did over torque the ignition coil and ended stripping the threads off IG coil 3- the boot is just barely tight but still held on good and coil firmly seated.*******


I am trying to figure out how to post freeze frame data here- Will upload it tonight-