Help me out with this. Yesterday I put the 4-wheeler and all of my hunting gear in the truck and drove 120 miles to our duck camp. I tried to do the speed limit the whole way there...I drove very conservatively in an effort to see how good I could do on fuel efficiency per the onboard computer (I do this alot).

With roughly 450 lbs of extra gear in the truck I got 18.6 MPG. I NEVER get that type of mileage. I normally get 13.5 around town (when unloaded) and maybe 16.5 on the highway. Yesterday I got 18.6 with a big, heavy, aerodynamic dragging 4-wheeler in the bed. Great I figure...I had just switched to full synthetic oil and was about to give it some serious credit.

Today on the way home I couldn't wait to see what type of mileage I could get WITHOUT the 4-wheeler in the bed...it was worse. The MPG's began dropping the moment I started the truck and they never approached the former numbers again.

The first 15 miles of my drive (leaving the camp) is a mix of 35 to 55 MPH speeds with no stops...on this portion of my drive the night before my mileage was still drifting higher from 18.4 to 18.6 MPG. My mileage should have at least stayed where it was...perhaps even gone up on the same portion on the return trip.

I have no clue how I could get 18.6 with a big load in the bed and worse mileage when I take the load out. The only thing I can isolate that was different between the two trips was a temperature difference of about 10 degrees, and the load in the bed. The same driver, same course, same driving style...different mileage.

Any ideas?

 

Unfortunately you cannot rely on the LIE-O-METER to accurately calculate your MPGs. It's an average value since the last reset.

Even resetting after each fill, I've personally seen it as high as +2.88 MPG and as low as -.91 MPG.

 

I've just never had that big a swing. I reset the meter after every fillup...I'm really not as boring as this makes me sound...I promise...but it does give me something to do when driving.

 

You could of had a tail wind pushing you with your 4 wheeler. You really need to do a few tanks and figure out your mileage after each tank by hand.

 

LOL. I understand.

Just trying to tell you that the LIE-O-METER is both inaccurate and inconsistent.

If you really want to track MPG, use a spreadsheet or fuelly.com (see my sig for mine).

 

Elevation also plays a role. If you were generally going down hill going to camp and going up hill going away from camp it will effect fuel mileage.