So first time posting here. Have 2020 Limited 5.7 4x4 with 3.92 gears. When i first got it we did a trip to Yellowstone and got 22-23 MPG. I just it 45,500 and did a trip this week and only got 15 on the highway. New tires same as what came on it. I do have a cracked manifold waiting on a new one to come in. Ex tech so I know this is causing some loss. But in town I average 11-13 which is bad. This is my 5th ram and non of them have had this bad of gas mileage. Have been thinking of doing a programmer or something. Am also thinking of getting the Stainless Works full headers and cat back exhaust. Any suggestion. I do drive slowly in town and watch how I accelerate and such.