Mysterious misfire
 

Hi guys, I relatively new here, I recently bought a 2013 g37 ipl and it has been misfiring ever since, I changed the coils and spark plugs, still didn’t go away, changes all the Lower and upper intake manifold’s gaskets still no luck. I’m getting these codes.
https://cimg7.ibsrv.net/gimg/www.myg...b86e85c59.jpeg

So I see Vent control valve (in tank) which is possibly old.
P0300 which will be the result of another faullt
p2138 which is pedal sensor Open or shorted which could be an issue with one of your throttles.

Having a throttle issue can develop a P0300 since the issue can affect multiple cylinders.

You'll need a better scanner to determine your fuel trims and throttle angles to further diagnose.

So I see you mentioned the vent control valve, I replaced that recently but the code still didn't go away, what I did is change the sensor that goes on the canister that's behind the right side of the rear bumper, but you said in tank, is that what I should've replaced?
also the p2138 code, you said the pedal sensor opened or shorted? what does that mean, and how can I go about diagnosing that and hopefully fixing it? I checked the gas pedal and there was some sketchy wiring done down there, if you have any resources for where these wires are supposed to go and how to go about undoing the sketchy wiring that would be great, last but not least how do I go about diagnosing the throttles and is there a position sensor on them I can change or do I have to change the entire thing, and how do I know which one to change (right or left)?

I was refering to "REAR" when I meant the tank. The sensor might not have been the fault and what you might be having is a leak in the canister or hoses towards the intake manifold. Since these hoses go from the canister all the way into the engine bay and get very close to your throttles I would say inspect this area for any disconnected wires, broken hoses, etc.

As for the pedal, the fact that you found some sketchy wiring I would say start there.

Feel free to post pictures as it will help tremendously. This connector feeds the ECM the position of the pedal so any broken wires here will lead to a throttle not opening or closing properly which would be your misfire issue.
Having bank 1 and 2 open differently can lean or richen a bank or affect both manifesting itself into a multiple misfire.

Good luck

noted, looks like I have a lot of inspection ahead of me, I will go ahead with that and post some pics of the sketchy wiring so we can figure out what's going on as soon as I'm back from vacation.