u/Massive-Might-1333

I have a 2004 Dodge Dakota 3.7L V6 and am getting a P0306 code after replacement of Spark Plug and checking coil pack by switching them. I’ve did stethoscope test on fuel injector and it seems to be working just fine. Any tips of what else it could be?

Edit-I just put a remanufactured engine into it two days ago as well.