Guys,

I finally got around to organizing two and a half years of gas mileage data.

My truck has roughly 28,000 miles on it. I recorded 25,835 miles of data. Some of the receipts were lost, illegible, etc. so they are not recorded.

Total: 25,835 miles per 1,842.8 gallons of gas. Total gas mileage is 14.02 MPG. Most of the mileage is what I'd consider suburban driving in Tulsa, Oklahoma. Because of Tulsa's unique air pollution situation, we have our own custom blend of gas. When I moved here from South Georgia in 2002, the gas mileage on my Tahoe and on my wife's Subaru both dropped noticably. I would expect an increase of between 0 and 0.5 MPG if I were buying my gas somewhere else.

I ran a linear regression on the data. While the raw data is quite variable, gas mileage for the truck over the truck lifetime trends almost perfectly flat.

I have the raw data in Excel spreadsheet form with a chart if anyone wants to host it.

One interesting subset of the data is listed below. This is from a road trip last September from Tulsa to the North Carolina coast. We were going 70-80 MPH for the entire trip with three adults, one infant, and a truckload of luggage. The AC was on for most of the trip.

Trip Mileage: 2,863.7 (around 250 of these miles were not interstate miles).
Trip Fuel: 163.99 gallons
Trip MPG: 17.46

Just for giggles, I deleted the trip above from the data set to calculate new overall mileage and a new trendline. Without the trip above, my average gas mileage drops to 13.68 MPG and trends downward significantly since the truck was new. There are a several things that could cause this:

1) My air filter was getting really dirty. I've since installed a K&N.
2) There was road construction near my house that forced me to take a slightly different route to work which impacted my mileage.
3) I've changed my driving style enough to reduce gas mileage (fairly unlikely). Edit: Upon further review, I actually think that a change in driving style is contributing to my decreasing gas mileage. Up until summer 2005, we always drove my truck on road trips. We'd do a 360 mile round trip visit to my parent's house about once a month. When gas prices went up in 2005, we started driving my wife's car, which meant no more highway trips in my truck. This made the relative mileage look worse because now it is mostly city/subarban driving. If anyone is looking for Subaru WRX mileage data, I have almost 75,000 miles of data!
4) Some other unknown item is impacting mileage, such as a different gas blend in the vehicle.

Unlike south Georgia/Florida gas, I don't see much variability between summer and winter, but I need more data.

Truck:
2004 Supercrew XLT 4x4
Lariat Wheels and Tires
Dual Flowmaster Exhaust
Uncover Bed Cover
K&N air filter installed June 2006
5.4 liter
3.55 gears

Feel free to ask questions!

Grim

 

Man, you submitting a report for school on this? jk

That's good analysis!

 

Nope. Whenever I fill up I always do the same thing--get the receipt, write down the elapsed mileage via the trip odometer on the receipt, toss the receipt in the center console, and reset the trip odo. It's a habit. I realized yesterday that I had over two years of receipts in my center console and decided it was time to clean up the mess!

I started doing it years ago as a way to track potential problems in my vehicles and to see if my mods made a discernable difference in gas mileage.

Grim

 

Do you have annual costs and trending for the costs per gallon. Also what kind of gas or brand to see if one type gets better fuel economy than another. I just ran two tank fulls in my 06 4x2. The first tank I got 19mpg (mostly hwy) and the second tank full brought me back to earth with 13mpg

 

Interesting, your numbers are close to mine. I have 35,000 miles on my truck, overall average is 14 mpg, highway is 18 mpg and city driving I get 13 mpg.

05 Screw 4x4 lariat

 

Good to see that kind of data so I know about what to expect with my truck.

 

Nope, I don't have annual costs and cost trends, but based on the data set that I have it would be easy for you to calculate (if you want). Looking at the raw data, it is very difficult to pick out trends without doing some type of data smoothing. There are too many variables that affect gas mileage.

The majority of the mileage data is based on QuikTrip, a Tulsa-based gas outfit. They do a very high volume here, so they almost always have fresh gas. They also have the cheapest fountain drinks around.

Grim

P.S. I'm still looking for someone to host the raw data if anyone has some web space available.

 

no doubt you are a statistics teacher. lol wow good data. I am too lazy to even reset my trip odometer.

 

I can host if for you. I'll send you a PM with my e-mail address.

 

 

I did a similar post a few months back. I too have kept records over about 30,000 miles. I keep a spread sheet in Excel that includes notes on how I drove, where I filled up, ect. I average about 16.6 around the metroplex and about 19.1 on the highway, driving 75 to 80 mph. I do not drive easily and in fact, just added the Edge last week. I keep the records out of curiosity. One thing I discovered that I had a hard time accecpting is that I get better mileage from Shell, Texaco, Conoco, and Mobil than I do the Qwik Stop type independents. I had always argued that gas was gas, but my records have indicated that I get about 10% better with a name brand.

 

I'll host the file for you if you want on my personal site.

Email me if you like.


I know Steve won't bring it up but his other site ownersite will track all this for you with reporting. Just an FYI.

 

hell yeah....ownersite.com is where it is at....

 

Did you say which engine and rear gear your truck has?

 

Your data aligns well with my fuel use. I've been posting it as I go along. Supercab, 6.5 bed, 3.73

http://users.cableaz.com/~kinzerford...s_Mileage.html