2015 pathfinder NATS problem
 

hi this is my first post to this group , am currently working on a 2015 pathfinder which was passed on to me by a technician friend, the engine idles very rough and loss of power on a high rev, there was no DTC so he changed the ignition coils,spark plugs,fuel injector set, fuel pump,throttle body,CAM sensors,CRNK sensors but problem was not solved, he passed the job on to me to swap the engine with another 2015 pathfinder which had a front accident so i did but after installing the engine the same old problem exist ,there was no DTC on the ECM even when i pull the plugs to the ignition coils to check for current so i suspected the ECU , i swapped the ECU from the wrecked vehicle to the one am working on, tried to program the key with the immo code 4145, 8377 and 5523 but was incomplete so i thought of swapping the whole immo system as well, took from the accident vehicle ECU,BCM,immo ring and key but it could not start the engine the starter only turns and the key lock icon stays on the dashboard ,a friend of mine advice me to add the SRS module and instrument cluster which i did but same no start problem , the key lock icon stays on the cluster the starter turns but engine not start NOTE when i fix back the native ECU,BCM and key the car will start. i need some help with what to do to start the car with the ECU of the other car