Check engine light - 2018 Platinum 3.5L V6

[mom2mgna]

I have a 2018 Expedition Platinum with 101,000 miles. The dealership recently had it for 12 weeks waiting on a transmission seal kit so the transmission could be rebuilt. I've had it back for a little over a month and noticed a week or so ago that it was missing upon startup. I started putting premium fuel in it and that improved. Then, today the check engine light came on. The fordpass app said it was an issue with the catalytic converter. I looked under the vehicle tonight after driving it and noticed a hose that was unconnected. After looking the part number up on Google I found that it was the vapor canister connector hose (circled in picture). Could this have caused any of my issues? Also, there was some odd noises (kinda like coins rattling in a can and the other part circled was sparking after driving)

 

[Bmac1955]

Sounds like a trip back to the dealership with your picture and if at all take a video with sound so they can hear what is the noise is. Probably vaccum line left unconnected causing to flash the engine light to come on but, the noise is more concerning if the Trans was worked on.