The link cswlightning provided should have all the ground locations? I didn't use the manual but instead read on the various vq forums about oem locations and grounding kits in general then hunted them all down and also made my diy added grounds.
The engine bay is easy enough as any black wire or cluster of black wires bolted to the engine or frame/panel is gonna be a ground(s). One in the battery box, one for the muffler to frame and iirc 3 under the dash of which I think 2 were relatively easy to get to.
I added 8 gauge crutchfield air tight ground wire to; transmission to throttle body, neg. battery terminal to t.b. and engine to t.b.. You can see the grounds on the t.b. and the one to the engine in front of the cam solenoid on the passenger side which just so happens to be an oem engine to chassis ground location and of which still is as such. All the other bay grounds are in the wheel wells now that I've tucked the wire looms. This is an FX35 and will be very similar.

 

Thanks! I used to have it on disc back when I purchased the car to help with the audio install. Lost it, so this is a huge help.

I still haven't found the neg grounds within the file, but the power generation voltage variable control system looks like it might need to be bypassed just to ensure its not the issue. I know it says that in the event of a malfunction, it will simply utilize the voltage regulator on the alternator, but I need to perform a big 3 cable upgrade anyway.

 

Boom! Extremely helpful. I didn't see this before I posted.