Car: 2005 350Z perf model ( 6 speed)

Symptoms: : No start, no crank, no dash lights condition when attempting to turn the car on. ( Dash flickers when attempting to crank, but almost like a bad contact type of flickering, not a constant pattern of flicker like when your battery is dead)

Things addressed: Changed Crank sensors, changed starter ( both under warranty). The car did have a bad starter and was getting the crank sensor codes. Taken optima red top for load testing ( passes fine), when no start condition is present jump starting the car will do nothing. I have 2 keys and when no start is present neither key works. Battery Terminals cleaned and tightened. Fuses checked and no issues found. No engine codes out side of the knock sensor harness( which I am waiting on from Z1). Car normally runs very well with no issues. I have also checked the clutch (switches?) behind the pedals and those work.

Observations: Car will turn on, run and charge battery when push started.
I changed the started and the car last night and the car cranked much stronger. On the second attempt the Z started having issues mentioned above. I jumped the car and nothing, them I waited several minutes ( in frustration) and then it started back up without a hitch. I then let the car idle for 5 minutes in between 4 start attempts, and all ended up working just fine. The Z randomly shows these no start issues, sometimes it works for days before symptoms re-appear.

I have checked all the fuses ( except the ones behind the battery) and my next step is to order a starter relay to replace my 13 year old one, perhaps its sticking...

Any help will be appreciated.

Relay Link:

 

Sorry for the double post, my internet took a crap mid post. Admins please delete 1 of em.