From a "50kw" dcfc going 20-85 you should get "50kw", which in my experience is around 46kw actual. From 85 to 90 it drops near 30kw.
Try to plan your dcfc stops so you leave at 80-85%
This may be related to the front contactor. You can confirm that when you have that reduced power again, view the power distribution and it will show no power to the front wheels while driving. It may be software related, I don't think there's been any definitive answers, it usually fixes itself.
The op receives the fault everytime he starts his truck.
Normally, when a trailer is plugged in it just gives a warning that the system is diabled, not a fault.
He also has trailer light issues which may or may not be related.
Blis faults can be caused by a few things. Contact your dealer to see if they have any background codes sent from the truck. If your connectivity is on, the truck uploads faults to a Ford server they can see online.
A recent poster broke their mirror which contains the indicator led. The...