Hey guys, I thought I loved my 2020 GMC Sierra 1500 3.0L diesel, it has plenty of towing power but VERY thirsty on DEF when towing. I have 7000 miles on it and I bought it in late June 2020. I have been struggling with visits to the service department at the local GMC dealer. The check engine light frequently comes on followed by a loud roar of the engine fan then the message "Service Emissions System" and then it tells me how many miles until it is going to reduce my speed. First trip they couldn't find anything, second trip they said that it was a loose wire and they fixed the problem, 200 miles later same problem. This third trip they say I need a "new pipe with a sensor in it" I am assuming NOX sensor? They say they can't find the part anywhere. In addition, when I tow my 6000 pound travel trailer this truck drinks DEF like crazy. I was having to fill the DEF tank every other diesel fill when towing! I ended up always keeping 5 gallons of DEF with me so I would not run out on the highway and lose power. In addition, the DEF gauge is NOT accurate. So my truck is currently at the dealer waiting for the part with no estimated time of completion. They don't want me to drive it so they gave me a loaner car, Buick Encore, sorry, not the same as a truck! I have been a Chevy/GMC guy for many years and have had both diesel and gas engines with no problems at all. This one is not great...research before you buy, especially if you are going to tow, you may want to buy DEF by the barrel! Thanks for letting me vent! Anybody else experiencing these issues?