I have a 21 Powerboost. I am having issues more frequently where it randomly "stalls". Basically, when it goes from electric-only to ICE, it just doesn't go, like the ICE isn't starting. It does it randomly and I cannot recreate it. The are no lights or any indication that there is a problem. I also have issues with the common 1 > 3 jump/slam. It is so hard sometimes, I have thought someone has rear-ended me. It goes away for 5-600 miles if I reset it in Forscan. The weird thing is for the last week I have been putting the truck in ECO mode and it hasn't done either but today I ran it in normal and it did both. I dropped it off at the dealership for service tonight but they said they are booked until after Christmas for "drive" issues. I was hoping that there is a software update that will fix it but our local dealership is less than forthcoming on any bulletins.

 

If you've never had a PCM update applied, there have been several available. I don't know if you need to apply them sequentially or if just the latest has to be applied. I've never seen anyone else report a stall issue, but at the very least the updates make shifting much better.

 

Any updated information on my truck, I have always had to get on here. My dealer is not the best and says they have to research anything, even when I bring them a printed-out TSB. The last time I took it in for the Blue Cruise TSB, they updated 1 module and said BC was verified working. When I complained they told me the tech verified it was working and I didn't understand how to use it. I got all the updates a few weeks later OTA because the service advisor, service manager, and GM all refused to contact me back.