Help! Car Idles Rough, Won't Accelerate, Service Engine Soon Light Flashes, Code P300

[NeoNz]

Hey,

So I come from the G37 forum, where it seems my problem doesn't exactly have an answer at the moment.

So some background.

Infiniti G37x 2012, 46k Miles
Mods: K&N Short Ram Intake, Fast Intentions Resonated HFC

In tried to install the FI RHFC and gave up when i couldn't get the top bolt out that faces the engine bay. Took it to midas, had them finish the job.

Performed the overnight battery ecu reset, start button ecu reset, still was giving me 0152 Codes, signaling my O2 sensors were shot, likely i did this when i was taking them out of my car.

Occasionally it would throw 0300 code, misfire? lean?

Anyways, I drove about 300 miles like this on my factory o2 sensors, and then swapped to new NTK O2 sensors (OEM) for Downstream.

Did the overnight battery ecu reset, start button reset, drove for about 70 miles, on the third time i started it up, no 0152 codes, but it went straight to a flashing 0300 code, i would clear it, it would come right back up. Car drove VERY SLUGGISH, almost like it was bogging and couldn't accelerate at all, would make a pop sound if i pressed the gas too hard.

Checked my K&N intake and found one hose off on the drive side. Zip tied that together, did a 5 min ecu reset and the car still ran like crap after about 2 mins of startup, scared to drive it now to be honest.

The odd thing is that after a ECU Reset, the car drives fine for 2 mins, then goes back to bogging, lean mode. Not sure what happens in this two mins, but i dont think it is my o2 sensors anymore, could be something on the intake side

I will check the vacuum hoses again and ensure there are no other leaks. COuld it be a bad MAF? How can i test my MAF? I ordered a bluetooth obd2 reader so i can check voltages and such tomorrow.

Anything else i should troubleshoot? I can take a video and post it to youtube, of the moment i start it up, and after 2 mins when it starts to idle very sluggishly.

I called FI and they believe it could be a vacuum leak.
I will put the stock intakes back on today if no more luck to try to narrow down the problem.
Thanks in advance for the help.

Brett