Hey guys have a question for y’all I just can’t figure out. So I have a 2012 Infiniti g37x sedan and I have full exhaust, wheels coils, and just got the 2.75 in intakes that a buddy of mine custom made, great quality and whatnot and said I would be able to run these with no issues, short story When we got them installed about 6 hours after my car started to throw lean codes tried just clearing them, asking him questions of why, he says the car needs time to trim and get used to the new air flow, i tried a idle reset, throttle body reset, ecu reset and it still keeps throwing the lean codes and he insisits the car still needs time to trim down, I’ve had them on since last Saturday and the problem persist, I wasn’t planning on getting a tune just yet so that is why I wanted intakes that I can run without a tune, please help, maybe you guys know something I don’t! Thank you!!

 

As far as I know, with respect to the G/Z, there's no way to increase intake volume at the MAF without a tune to account for it.

This is a hard stop. Put your new intakes on a shelf for a while, and save up for the tune.

And let's see pics of this custom setup. You sound proud of it.

 

A friend made them means possibility a "fabricator" who saw and replicated what he saw without the proper research. Anything bigger than the factory 2.5 needs re-scaling.
They're still good however they need tuning for them to work properly, put the stock ones back on until you can get flashed/tuned and then you'll be able to enjoy.