Drop in mileage.

[Jordan H]

For years I've consistently gotten 10 mpg in my 8.1 liter Yukon pulling my 35' Montana Mountaineer. Recent trip 1400 miles it dropped to 6.9. Mileage without trailer hasn't changed. Had brakes check and bearings before I left, could that have anything to do with drop in mileage?

 

[Germanrazor]

Well if your getting the same mileage not towing and nothing has changed as to weight or added to affect aerodynamics, that could most certainly be “a” possibility. However, I find certain gas stations and quality of that fossil fuel thing to also affect gas mileage.

 

[Jordan H]

Well if your getting the same mileage not towing and nothing has changed as to weight or added to affect aerodynamics, that could most certainly be “a” possibility. However, I find certain gas stations and quality of that fossil fuel thing to also affect gas mileage.

Thanks for your response. Good point on the gas source but for the most part I stopped at my usual stations unless the regional suppliers could be a variable. I'm going to check the torque of the bearing lugs although I had no noise and did not notice excessive heat. I'm having my Mechanic also check out my Yukon as well, just to be sure. Thanks again

 

[LSG]

I did not see where your from or where you tow.

Your mileage is fairly close to what we see here from the same engine and tow rig.

If your area is just now moving to higher ethanol fuel levels that is most likely the cause. Ethanol has a lower BTU less energy for a given volume of fuel over gas. And some areas are just now seeing higher levels were 15% or more on any given day. There are places that have had less than 5% up until recently.

So you think well I’m going to run premium. Thats an option but the cost difference here equates to about the same money when its done and ethanol has been proven to be fine in later model cars and trucks and the newer the more adapt they are to it. Fact is if we had cars to run on pure ethanol there lifespan would be longer so dont think the ethanol fuels are bad. Some small engines dont perform as well on it theres reasons one is you take 15 to 20% of the power away from a 2 hp engine and its noticable next ethanol’s do not store as well and we put our lawn equipment up with ethanol in them for half the year quite often thats where the two main differences are

If you show a loss of power unloaded and the mileage drops you might have other issues. The list of which is to long to throw any real thoughts out there. But 8 MPG loaded with a trailer isnt to far off.

I have a diesel tow truck and I talk with other tow truck owners with the same truck in gas that get 6 to 7 MPG loaded and our weights are not that much different than your tow rig and a trailer just for some comparison mileages.