What’s your MPG’s while loaded?

i am loaded right now with a 36k load going 1080 miles, right now truck is saying 5.1 MPG,

when I left the house I took a load 1801 and average was 5.41 and that was me using a calculator to see if the trucks dash was correct.

when I pull a hill or grade, I’m getting a sputter in the higher gears. So I know slowing down and so on is correct but I believe I have a mechanical issue and that’s what I’m trying to figure out. It’s like it’s looking for more air or fuel.

 

Yea that sounds like a mechanical issue. I'd get that looked at asap. Could turn into something larger if you live it too long. To get a 100% accurate fuel mileage and track it. Download fuel gauges from let's truck. It's free and keeps track of past fuel up and gives you 30,60,90 and lifetime averages. My dash is reading 7.2. So its way way off. What engine do have?

 

I have a Cummins isx 15, and I will download that app.

 

What's your rpms when climbing? Should be downshifting around 1500 and upshifting at 1800. Those cummins don't like to be lugged.

 

I’m doing just that, I have a 13 speed. So when I get to hill or grade down shift to 17-1800 Rpms and again at 1500