Ok just read this entire thread. I have a 2018 2500 crew, I’ve had it for a little over a year, all stock, drd emission tuning, 55,000 miles and my truck does the exact same thing. It doesn’t really feel like it’s geting close to dying but it surges until trans gets over 90deg and the engine gets to 100deg +\- and it only seems to do it when ambient temps are mid 40s and below, mostly in the morning when I leave for work.

Ive got to take my truck to the dealer one day next week for a recall. I’m going to set mine back to stock a few days before I take it to the dealer and see if I get the same behavior. If I do I’ll tell the dealer to fix it. What do you guys think? Bad battery(s) on such a new truck?