I have a 2021 F150 2.7 liter ecoboost. 41k miles. Didn’t start on a Monday. Disconnected the positive battery cable and reconnected it and it started. Same thing happened 2 days later. The next day it started fine and put in drive and it would not go over 6-8 mph. Truck shook violently. RPM was up near 2000. Sat parked for 10 minutes and eventually got it home and to the dealership the next day. Dealership has no answers. I know very little about trucks just as a disclaimer. Any ideas??