So I have been diagnosing a P1283 issue on my 2005 G35 Coupe. The procedure without Consult-II according to the manual requires me to run the engine with the MAF disconnected. When I do the engine doesn't idle but cuts on for a brief moment. Then throws a P0113 code which is IAT too hot. With the IAT integrated into the MAF what would cause this reading if it is disconnected?

P0113 is for excessively high voltage, not excessively high temperature. The IAT is a negative-going (NTC) circuit, so the voltage rises as the temperature falls. Since the circuit is pulled up by the ECM and pulled down by the sensor, it will go to full voltage and read "Siberia" when disconnected (usually -44F).

Alright thanks for clearing that up for me. But I still have the issue of it not throwing a P0170 code as prescribed in the diagnostic procedure. Probably due to the fact it won't stay idling for the amount of time needed for the computer to diagnose it.

Update: I decided to look at the freeze frame for the code and found STFT to be at 16% on bank 2 where bank 1 was around 10%. I am going to clean my injectors and see if the code returns. Will update.

P1283 resolved (for now). Added gumout to fuel tank today since I suspected clogged injectors as mentioned before. So far CEL has not come back and also my car will run with MAF disconnected. I may still need to inspect my plugs/coils as my STFT is +25% and LTFT is +10%.

If your scanner has work support to do it, you should clear the LTFT. The direction it goes and how quickly it goes there will tell you a lot.

I'm back to suspecting O2 sensors as the fuel system bank 1 and bank 2 will briefly show OL-Fault at idle. I'll be testing them when it stop raining.