Does anyone here have a wiring harness diagram for the engine bay? Specifically one that is a little more in depth on how to lay the harness around the engine, intakes, etc. and also bracket mounting locations?
2003 Z

 

I would look at sources like ebay or google image search for the harness - it’s sorta self-explanatory at some point.

 

I would say consult the FSM, but unfortunately the diagrams for wire harness routing are very vague, it doesn't go in depth about which hoses/piping/brackets you need to route the harness under, over, or clip to (etc). As Beall suggested, I would look at a combination of high-res photos or videos covering different areas of the engine bay.

Also note: The wiring/routing between years is not all the same. You should try to stay focused on 2003-2004 350Zs and if you have a 6MT, match that.

Good Luck!
-Icer