BoostedK420

Hey everyone I have a 2004 350z with the VQ35DE! Motor locked up so I got a used one same engine VQ35DE RWD so the problem I’m having is everytime I try to start it it’s very sluggish and will not start! Yes sounds like a dead battery but I can promise you it’s new! Changed the starter as other forums pointed to that changed both cam sensors and crank sensor with OEM new! I’ve checked every ground put in these cars from the factory cleaned and reattached every single one of them! Checked connections cleaned and reattached every connection at the starter and the alternator all the way to the battery! No codes no codes no codes! I’ve checked compression and I’m 181-184 on all 6 cylinders. I just did a leak down test today and it passed timing is tight and I’m now just lost! The weird thing is say I try to crank it a few times and use a little battery power I have a big boy charger starter and a jump starter that can jump off a semi but for some reason everytime I try to start it it’s really sluggish and if I have the cables connected to another vehicle it even draws the other running vehicle down! I thought had to be a main power feed or bad ground but when I tell you I’ve pulled the schematics and checked them all I promise you I have! Has anyone had trouble like this when replacing engine and if soo please inform me of what little issue I am missing to solve this! I have been racking my brain forums other brains anything for 4 months trying to figure this out! So Please Help if anyone can! Any questions please feel free to ask I’m an open book and just don’t know where I should turn next!