6.0 ICP Issue

sorry to keep creating new threads but i will post an answer if i ever find one. shooting my last shot before it goes to a shop. just see my profile or ask questions if you want backstory. but my question is how does the starter connect to the icp sensor? because i’ll have 300 icp not cranking and the truck will start but immediately die and the starter will kick out and try to engage again and grind. but icp unplugged it starts and the starter works great. if i use the starter wire on the battery with key off it will also crank fine. the issue is not in the sensor and not in the harness. new OEM sensor and harness. the harness is brand new oem that i’ll put in tomorrow but i swapped in a different harness that had the same issue and some other issues so i’ll swap it again for one that i know is good tomorrow