10 MPG highway in a 2012 Denali???

Discussion in 'Performance & Fuel' started by Kady, Aug 16, 2012.

  1. Kady

    Kady Epic Member 5+ Years GMTC Chick 100 Posts

    No, I wasnt driving in M mode. And i know what a truck feels like when it shifts... and this wasnÂșt shifting... it was something else...
  2. dobey

    dobey Epic Member 5+ Years 500 Posts

    Can you post a video of it happening, showing the tach/speedo, and with the sound of the engine (if you can, as it can be hard to get the engine sound sometimes). And describe the movement of your foot or if using cruise control?

    It's hard to say what things are exactly, without being able to see it. There's also a lot more integration between the transmission and the engine control on the newer trucks with the 6-speed autos. So, it may still just be shifting, though it might feel a bit different than you're used to with the older series of engines/transmissions.

    If it's a brand new truck though, I do wonder if maybe GM has done something to their 2013 vehicles that makes them a bit off. I test drove a new Sonic recently with a 6 speed auto in it, and the transmission was behaving very oddly driving around town. I noticed that it would shift up/down between 2 gears a lot just holding my foot steady at ~45-50 MPH, and the shifting felt very odd when accelerating to speed, and when slowing to stop. I repeatedly mentioned the weird behavior to the salesman in the car with me, but I don't think they did anything about it, and the car was sold only a few days after that, and I never noticed it moved from where it was parked for display, until it was sold and I saw the new owner driving it on the road. It may have been a simply issue in the programming, and I wonder if perhaps the same or similar issue has happened with the truck you're discussing here as well.
  3. Kady

    Kady Epic Member 5+ Years GMTC Chick 100 Posts

    Its not my truck, I was only doing a favor by bringing it to the dealership for my friend since she works so much, so I won't be able to get that video for you..
  4. boos sierra 2500hd

    boos sierra 2500hd New Member

    Just something to try ?? I read were someone was having similar troubles and they found that the traction control needed reset.. All they did was turn it off and on a few times while driving at about 30 M-Hr ?? Can't hurt anything to give it a try ?? Good Luck !!

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