2024 Chevy Silverado 2024 3.0 Duramax. Please note i am using a scan gauge iii for my data and now. I've had my truck about a year now and up until recently i was getting and impressive 33mpg.

These are the issues so far could use some help since dealership isn’t taking it seriously. I noticed a few weeks ago that i get a weird grinding metal noise under the truck sometimes at.