[Hayden_69]

I recently just got my 2016 rallye back after having a engine swap and as soon as I started it starts rough for a min or 2 then slowing back to normal . I opened the hood and noticed a wire from the engine wiring harness just dangling in the back . A black and green, 2 wire to a connector. Any help ? ( the mechanic that did it obviously isn't worth a damn )

 

[SRT-8Charger]

Let me look tomorrow in the daylight. 3.6l V6 right? I think that is the crankshaft position sensor plug. It plugs in on the bellhousing underneath the passenger side head. It's easier to see under the car.
That would explain why it's running wonky. It's only running off of the cam sensors. You should have a check engine light. Have Oreillys or Autozone check it for codes. That would help give a clue possibly.