I've read every forum possible and so far none of them said what the cause was. I put in a IPP stage 1 long block everything sounds and runs good. The only problem is I'm leaking oil out of the front left bolt if your looking at it from the bumper. I have done permatex, and the 2nd time doing it I did Nissan factory OEM rtv, and the 2 new o rings that sit where its leaking. I assume at this point it's the upper oil pan itself now. Any tips, comments, or suggestions will be greatly appreciated. By the way its a 2003 350z. I do have a single turbonetics setup as well.

 

I would suggest posting pictures...