2013 G37x AWD Sedan P0300 and airbag light

[idiom]

Hi Guys, NuB here.
I have this flood car getting fixed.
So far running, but rough. Has P0300 error-multiple misfire and Airbag light is blinking.
Replaced bunch of modules.
ECU was from 2008. And got used SRS module.
Spark plugs and coils look OK.
I suspect there is shortcut somewhere in circuit, but cannot figure out where. Is there circuit test/diagnose instructions?
Can anyone advise?

Just one thing remembered - doesn't go over 4500 RPM and moonroof motor starts grinding sometimes while accelerating.

[audtatious]

yeah, I'd highly suggest digging through the FSM EC.pdf which goes over error code troubleshooting.

Good luck with a flood car, that would be quite a pain.

http://www.nicoclub.com/FSM/G37/

[idiom]

Yeah, looks like it will. but p0300 is not that complecated code. hope to figure it out soon.
Airbag will be the pain i think.
Thanks for link!

[RED_DET]

On most flood cars, every sensor is normally replaced for the simple fact you don't know which on is going to short circuit next. You could be chasing your tail to the end of time, good luck.