I recently replaced a VQ35DE in my Nissan 350z with one that was imported. I swapped the engine successfully enough for it to run and drive( first swap ever). I am trying to get the car to idle more stable and get rid of the CEL. I haven't driven it much because it tries to die when in park and in drive stopped at a stop sign. It felt like it was in limp mode as it wouldn't open up. I fixed a few vacuum leaks which seemed to help the idle and acceleration. Yet, once started it will idle okay and then drops the RPMS to almost dying then picks back up around 900 RPMS and it continues as its heated to regular operating temperature. I feel like I've tried everything to my knowledge for the idle. I have reset the ECU and the CEL is still on after the whole process. No codes pop up and I'm at a dead end. Any advice on what to check for the idling issue? I also replaced the throttle body and spark plugs. Any advice for the CEL. Anything helps thanks!

 

No need to double post