Re: Trouble codes and random shut off
Welcome to the garage.
The P0112 code could be due to a failed IAC sensor or open/shorted wiring to the sensor. I would start measuring the wiring and if found ok, change the sensor. This faulty inlet temperature sensor info will lead to the higher fuel consumption.
Regarding the random shut off, have a look at the wire bundle which runs behind the cylinder head, it can rest against a stud and wear the wire isolation through, causing random shorts.
If ok, i would change the crank position sensor.
Indeed the screws from some PCM´s can be too long, causing an internal short in the PCM.