I bought an 07 350z base the other day and was told the oil pressure sensor was replaced and the gauge inside was just faulty. It seems to work perfectly fine when I'm driving, but at idle it shows very little to no oil pressure like maybe 5psi.
I am just wondering if there is something I should replace/fix that can cause little oil pressure.
I know it has an upgraded exhaust, clutch, and springs but everything else is stock. If that helps at all.

 

Well, I'd have the oil pressure checked ASAP with an external gauge, just to verify, because there are other issues besides the sending unit which an cause the pressure to be low. This is not a "wait and see" situation - do it now.

 

And this is one of those other reasons: