Confused about MPG in 03 Taco

[3 DOGS]

Are there different "settings" for the Tacos? What I mean is can a Taco be set up to run "better" or a certain way depending on the location it was sold? Is gas "different" state to state?
Here's the situation:
Last year I made trip to Colorado from Omaha. My average MPG in Omaha was 16-18.5 city/highway (unloaded). On I-80 to Colorado I got 13 mpg/75-80mph (loaded) - figured it was the head-wind. Once in Colorado I got 20-22 mpg/70-80 mph (both loaded and unloaded). I traveled to Colorado Springs and then to Burns - the White River National Forest.
Over the past year here in Omaha I averaged 15-18 mpg. Again this is city/highway combined.
Last week I did the trip again. On the way out I got 12-14 mpg (loaded) 75-80 mph. Once I hit Ft. Morgan and fueled up my mileage went up. Eventually I got 19-24 mpg!!! 24 MPG WOW!!!!!! This was during my travel in Wyoming from Jackson to Rock Springs @ 70 mph. Then from Rock Springs to Omaha I got 20 mpg/75-80 mph.
Side note - by loaded I am talking up to another 250 pounds of gear.
I have changed fuel brands, the fuel filter, air filter, tires and so on. I have tried 87 octane and 92 octane. The best was with the 87 octane fuel. I just cannot figure out why in Colorado and Wyoming my 2003 Taco DC 4X4 V-6 gets so much better mileage.

Is it programmed for higher altitudes? Is gas that much "better" in the mountain states?

Any ideas or advice??
2003 Taco DC 4X4 V-6 265/75/16 Hercules Terra Trac AT, Snug Fit topper

 

[crawler#976]

Is your local gas mixed with 10% or more alcohol? Did you notice if the Colorado gas had a similar content?

Alcohol doesn't have the same energy content as gasoline. The E85 (85% alcohol/15% gas)flex fuel shows a marked decrease in mileage over gas, so if the gas in Colorado is free of alcohol, it might make some difference.

What is your local elevation?

As I recall, Omaha is at roughly 1000' elevation, so part of the poor economy on the way to Colorado is gaining 5000 feet of elevation. I have noticed a significant increase in mileage when driving at high altitude (over 9000') for a week in two different Toyotas. Part of that was probably due to the leaner mixture, and the slower speeds. Perhaps your seeing something similar when your at 6000'.

What was you mileage returning?

 

[Wanderlusty]

Had similar results for the Trophy trip. Similar truck. 2004 DC Taco. Got better mileage and generally ran smoother on the return trip, as I descended altitude, generally speaking, going back east. The gas I got in AZ and NM seemed to give better mileage results, though I did not take note of the specific content, though know NM was lower octane than I use back home. There was actually a couple of stretches I somehow achieved 20+ mpg despite the 255 tires. I was lovin' that!

 

[tacollie]

I live in Colorado and have seen similar mpg. My dad lives in Kansas. Every time I go out there I get 20-22mpg. Coming back I get about 15. coming back is all up hill and there is usually a horrible head wind. Driving around in Kansas at 1800ft I get about 18mpg but the truck is a little quicker. Up here at 6500ft I get 20mpg and the truck is a little slow. The air is dryer here to. Plus most the gas in Colorado is 10% ethynol if I remeber right. Please correct me if I am wrong.

 

[Martinjmpr]

I think there are too many variables that are being left out. All of your MPG results seem to be within the normal range.

Here are some things that would be good to know:

1. Bed covered or not? Shell or no shell? If there is a shell or cover, what is it made of?

2. Cruise control or not? If CC is being used, at what speed?

3. What time of year were you in CO? The reason this is significant is that many parts of CO use E10 (10% ethanol fuel) during winter months to reduce pollution. As has already been mentioned, ethanol returns worse MPG than pure gas.

4. What kind of driving? Heavy traffic or open road?

5. Does your AT have a "power" and "economy" setting?

6. Do you always fill the tank to the same level?

7. Was there any change in tires that could account for the difference in MPG?

8. What were the weather conditions? Was there much wind? Crosswind, headwind or tailwind?

Here are a few things to remember about MPG:

a. MPG drops off sharply after about 55-60mph. To get your best MPG, set the CC at 60 and leave it there.

b. If you are measuring MPG by using the miles traveled on the odometer, it's obviously important to know if your speedometer and odometer are correct. On most vehicles, they're off by some amount. Use a GPS to measure both speed and distance travel. Once you know what your actual speed and distance traveled are, then you can adjust your figures accordingly (fyi, my '04 Taco with the stock 265/70r 16 tires and steel wheels is the closest I have ever had to a properly calibrated speedo and odo.) Changing to a different diameter tire will change the odometer and speedometer readings, so you need to account for that.

c. Crosswinds and headwinds will worsen your mpg, tailwinds will increase it.

d. Higher octane fuel is only effective if you are experiencing knocking (pinging.) If you are not experiencing pinging, higher octane fuel will only suck up more money and probably make your MPG worse.

e. Bigger tires increase unsprung weight and sometimes increase rolling resistance (depending on tread design, width, etc.) which can also worsen MPG. Supposedly narrower tires should be lighter and result in increased MPG, but I've never tried this.

I wonder if maybe on the trip across Nebraska you were primarily filling up with E10, and when you got into Colorado, you switched to all-petro, resulting in the increased mpg.

Interestingly, I have found that I get much better MPG on 2-lane roads, even if there is a lot of up-and-down travel, than I do on interstates. I think it's because it's so much easier and more tempting to maintain higher speeds on the interstate.

 

[teotwaki]

Dancing with ARCO

It is funny how some of the direct questions about performance are listed but the answers wander off into hand waving...


What is oxygenated fuel?
Oxygenated fuel is gasoline blended with oxygenates like ethanol. What that means is that the gas contains more oxygen so it burns cleaner, significantly reducing auto-exhaust emissions, particularly carbon monoxide and hydrocarbons in older-model vehicles. Newer-model vehicles have sophisticated engine-control systems that minimize the benefit of having more oxygen in gasoline. In addition, refiners can make other changes to the composition of gasoline that achieves similar emission reductions without the use of oxygenates. Currently, federal regulations require oil companies to produce and sell oxygenated fuel year-round in many major cities in the U.S. State regulations also require oxygenated fuel in the winter for cities that have carbon-monoxide problems.

Will ethanol in ARCO-branded gasoline change my car's performance?
BP's oxygenate choices in ARCO-branded gasoline reflect our commitment to gasoline quality. Tests by BP and others show that use of ethanol should not harm the engines and fuel systems of modern vehicles.

How will ARCO gasoline with ethanol perform in my car?
Ethanol-blended ARCO gasoline should perform in engines similar to the way our previous gasoline did. With any oxygenated gasoline, there will likely be a slight reduction in performed fuel economy by approximately one to three percent.

Can I use ARCO gasoline blended with ethanol in my antique car?
Most cars' fuel systems with either fuel injectors or carburetors manufactured since the early 1980s were made with materials designed to tolerate oxygenates including ethanol. Therefore, most modern cars should run just fine on ethanol-blended gasoline.
For antique cars, owners should consult with the manufacturers for compatibility of ethanol blends with antique engine parts. If ethanol blends are used, regular inspection of the fuel-delivery system by trained mechanics should be undertaken.

Does use of ARCO gasoline with ethanol improve air quality by reducing emissions?
EPA's Blue Ribbon Panel for oxygenates determined in 1999 that the use of oxygenates including ethanol has little benefit on exhaust emissions from modern cars. The reason for the lack of benefit is that modern cars already have very low emissions and modern engines control the combustion process so that the oxygenate benefit to the fuel is nil.
Ethanol has been shown to reduce carbon monoxide (CO) pollution in older (noncomputer-controlled) engines. With this reduction in CO, there may be a tradeoff from using ethanol blends because of their higher emissions of volatile organic compounds (VOC) and nitrogen oxides (NOx) that contribute to ground-level ozone pollution. In addition, ethanol blends may produce higher levels of aldehydes in exhaust that also contribute to air-quality problems.