Engine wiring diagrams please?

I live in Arizona, I purchased this car last April, went on a week long trip the day after I bought it. The car sat fine while I was away, upon returning home I drove the car for about a week, normal trips to the store and work. I am not hard on vehicles by any means, I keep them maintained and fueled by a 1/4 tank I am already filling it up again. I noticed the reduced engine power first in August of 2018, it was an especially hot day and I attributed it to just overheating maybe. I had it checked out and got nothing from the dealer, saying they could not read codes for what I was experiencing. I showed them the photos I took and they said it could not be the same car because those do not show up. I don't even know why they would assume I would want to was my money or time at a dealer. Shops told me it is this or it is that so I had everything suggested replaced. Here comes the list: Battery, throttle positioning senor, throttle body, air filter, camshaft positioning sensor, ignition switch, fuse box, power train relay. Pedal, BCM, was cleaned and re connected. Thermostat and temperature sensor also replaced.

This problem still persisted until October of 2018. Then one day it just stopped. The weather was cooler and the car was running great. In march 2019 I managed to replace the manifold due to a crack in it, car was running even better after, of course thankfully lol end of April 2019 beginning of May 2019 the weather was heating up and the car started acting up again throwing a laundry list of codes and my air bag light started coming on randomly on the dash and then it would switch off.

I am at a loss and was hoping someone would have any thoughts on the ECM being bad. I am not familiar with the voltage part and what it should read, but I can figure that part out. I don't know if the heat matters with the ECM but I would assume this only because the ECM seems to be the last thing I have looked into that I know of.