Massive Drop in MPG

[bipock]

I've had this truck November, bought new, no mods. I basically drive it from home to work, with a stop to drop off my son and neighbor at school. Run the same route, same speeds everyday - fairly open highway at 62mph, cruise set 85% of the time.

The last couple weeks, I've gone from 23-24mpg to 19.5. I've checked tire pressures and they are remaining consistent. I don't tow anything, no extra weight in the truck. No super fast accelerations or any kinda of crazy driving.

What could cause my MPGs to decrease this much over the course of a month or so? Anything I should look at?

 

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[pinebaron]

I'm totally guessing but due to the gas crisis, pumps may have commenced selling lower octane fuel, resulting in an MPG drop.

 

[Phil-AT4]

I'm totally guessing but due to the gas crisis, pumps may have commenced selling lower octane fuel, resulting in an MPG drop.

Or they could be selling gas with more ethanol in it.

 

[Akcajunz]

Gas or Diesel? I have a 2025 1500 AT4X with the 3.0 Duramax and I am consistently getting 26-29 mpg. 70 mile round trip to work mixed interstate and city. I know most gas stations are probably filling their tanks with summer blend fuel, however, according to the almighty Google, octane levels are not affected between winter and summer blend fuel.

 

[TX_Critter]

You didn’t say which engine, if it is the 3max then you may have hit a regen. I usually see a drop like you mentioned while it is going through a regen cycle, I’ve also noticed that wind direction can make up to like 4-5mpg difference…

 

[gemarsh]

I would watch the real time fuel milage screen on the DIC. That is about the only way to tell when your babymax goes into regen. Unless of course you have an aftermarket device watching it.

Burning the soot out of the dpf, really drops the mileage. But it shouldn't effect the mileage over a long duration. It should regen, what?, every 500 miles or so?