I just got a 2021 Chevy Tahoe a week ago. When I fill the tank it shows 350 miles range (Should be much more). Also, when I get down to showing fully empty tank I still have around 8 1/2 gallons left in the tank. Is there any way to re-calibrate the fuel gauge. I don't feel like sitting at the dealer all day again. Any help would be greatly appriciated.

 

You need to drive it more.

 

Drop it off and demand a loaner. You paid a lot of money for that truck. They probably will have to drop the tank and replace the sender.