So last august, I purchased a 2006 g35, with a partial built shortblock and greddy TT kit installed. The other modifications aren't really pertinent for the problem I have currently

When I put a code reader to it, I'm getting the codes p1084, p0507, p0037, and p0057. twice (x2). I'm not worried about the p0507 or the p0037 and p0057. Just recently tried replacing both bank one and bank 2 on the heads, with an almost catastrophic failure when replacing bank 1 (found out it was the wrong sensor) but that was corrected quick. I'm still getting the p1084 code, and I've recently found out that there's another sensor located somewhere near the oil pan.

Can anyone tell me where it's located, and also the serial number for the part? I want to get this corrected asap, so I can get retuned and get rid of the shitty one that I currently have now (runs lean on e85, afr on average is 14.3-15.5 at stop and cruising speeds, drops to 13ish0 +/- 0.6 under heavier loads...when it wants to).

Also, does anyone know where a boost leak is most likely to occur on a greddy TT kit? I'm sure I have one; the car is supposed to peak @ 12psi, but I'm restricted to 5psi in any gear...I'm not too knowledgeable on turbo systems, but I'm trying my damnest to learn all I can.

All inputs are greatly appreciated!