Following. Just had to tow my 2021 Sierra 1500 SLT with the 6.2 into the dealer as well. Stopped and filled up with fuel and on the way to work it started to misfire and shifting hard. Stopped at another gas station along the way and parked it and had a buddy that I work with come pick me up. Returned after work to haul it into the dealer and went to start it to put it on my buddy's trailer, it started running real rough with the check engine light, service parking brake light, and check ECS light all on. Started second guessing the fuel and everything but had my receipt that said I had got premium fuel and not diesel. Truck has 10k miles on it and looks terrible being pulled into a dealer by a Ford.....LMAO