Primary to ignition coils and MAF sensor wiring diagram

Hello. My friend bring me his vehicle because it has a check engine light on. One code for the IAT sensor and I found something more. Someone change the plugs of the ignition coils but they use a butt connectors to make the connections. I want to know if the wires are correctly connect with the diagram and change the butt connectors with welding. I need the MAF sensor wiring diagram to test it and see if there's a problem on the connector, the wires or the ECM, PCM, ECU.
I appreciate your help.
Thanks,
Juan Marin