We just made a 1000 mile trip to AZ from KS, and for the first few hundred miles, it was stuck in Regen and was losing power.
I was down to 55-60 mph max.
I was fortunate to find CJ Auto & Diesel in Dalhart, TX. The guy there told me (on the phone) how to fix it - stop driving and just let it run for an hour while parked.
Apparently, when driving, the DPF never gets hot enough to do its thing.
It worked. Running much better now and the DPF meter in the vehicle info screens shows empty.
The guy was accommodating and clearly knew his stuff.