I have exactly that problem. I park on a small incline and my fuel gage is always off by 2 small lines. When I stop and park it on level ground and restart, it is ok. I think it does change back after I have been driving about 15 min. However, the digital readout on fuel used seems pretty accurate. It probably measures fuel going into the injection system, and thus is only looking at fuel actually used (I think).
Opps, I'm now not so sure about my comment on the digital fuel used readout being more accurate. Went for a ride today, and I think it was reflecting the fuel guage. I'm gonna have to start writing down the numbers at start and finish.
That you could send me via email.. I have the April 2019 version but understand there may be a Jan 2020 updated version.
Vehicle tires are at 3/32 and dealer says I need to pay 70% including his markup! the april 2019 version say 42% at 28K miles... Is the stealer trying to take me for a ride???
I am very discouraged and disappointed with GMC. I purchased my GMC Acadia All Terrain on 8/24/17.
4/4/19: Michelin tires were worn down to 2/32. I was offered a discount for continental tires and replaced 4 tires. I still had to pay $600.
5/23/18 – Vehicle had to be towed. It stopped moving...