Gas Mileage

Man I just took delivery and I'm getting 17-18mpg but only 2nd tank, it's 17-40 degrees where I am at, 4500 ft elevation, and I accelerate gently like a grandpa to see if mpg gets better but it doesn't. 70% of my miles to this date though are local driving (we got a crapload of snow). YMMV (your mileage may vary?)

 

So many of these threads with mileages that vary all over the place. Different drivers could drive they same truck and get widely different mpg due to how they drive. Drivers who are similar in how they drive can live in totally different terrain or city traffic and get widely different mpg.

If you say you get 20 mpg that means nothing anyone can compare it to without a lot more information. What model truck? 4WD, 2WD, auto or manual? Any mods? Tire size? Lifted? Regear? Where do you live and is it hilly, flat, low traffic rural, mostly city?
What is your average speed over that tank of gas you have your mpg posted at? Are you an aggressive or moderate or slow driver? Are you running from the cops? Are you an asshat driver whipping in and out of traffic? Are you the model speed limit driver or the one who drives 4 miles under the speed limit (malicious adherence) who annoys the other 95% of us on the road?

Provide the answer to these questions when you post your mpg or it means nothing! Post #50 shows how it’s done right. And quit rernin’ my life with these “not enough information to mean jack squat” posts!

P.S.
Y’all have a wonderful weekend!

 

Same here. I just closed out my first year of ownership and of the 50 fill-ups (she sat for 4-months while I rode my motorcycle around the country) the following is my fuel consumption summary:

- AVE: 18.78 MPG
- MAX: 21.39 MPG (mostly highway)
- MIN: 14.42 MPG (IIRC, I was towing a trailer)
- DIST: 11,135.9 miles
- FUEL: 593.114 gallons
- COST: $1,662.91
- COST / MILE: $0.14933
- AVE Price / GAL: $2.80
- 26 of the 50 fill ups was at or above the average MPG

 

For the longest time I couldn't get my AMPG to move above 17-18 on a stock taco for the most part. It was pissing me off! I typically refuel with truck running. Why waste good heat or ac! Anyway I recalled reading you should shut it down when refueling to reset the computer related to AMPG. So today I did and WALA! After a decent drive of mostly city I got and average of 23 MPGS at the end. I was driving like I have a depth perception disease! coasting, neutral on downhills, no run ups to red lights, you get the idea. The kind of driver we all have wanted to shoot!

Anyway. Always kill the truck when refueling.

 

Neutral on downhill runs won't save any fuel, the DFCO should kick in if you leave it in gear.

 

Leaving your vehicle running while fueling up is a great way to mess things up. The fuel system is pressurized and needs to stay so when it is running. If you hang around after you shut off your engine, you'll hear it maintaining this pressure.

 

HMM. The truck likes to upshift on a downhill. Costing momentum. Neutral Running below 1k rpm seems like I get some free movement. Please explain DFCO. Mind you I don't do this all the time! Im not some MPG freak! Its just fun for me sometimes to see how many mpg I can squeak out.

 

Deceleration Fuel Cut Off

 

It stands for deceleration fuel cutoff. Basically any time the vehicle is in gear but coasting, it cuts fuel to the cylinders to save gas.

 

Regardless of fuel shutoff it still should save you fuel in the sense that the speed loss due to transmission braking gear loss will be reduced in neutral (i.e. coasting downhill). You’ll be at a faster speed at the bottom of the hill thus requiring less gas to get up the next hill. I don’t do it now but playing around back in the day Ive done that, saving gas when we were about out of gas as poor kids lol. I think we typically did that with manuals, using the clutch or maybe shifting to neutral on a long hill. But we did it with autos as well. Reading on the internet they say don’t do it and it doesn’t save and warnings about shifting to gear from neutral in an auto, so I can’t say about modern vehicles for sure. I can say we got to where we needed to go with not much gas and it did help in those older models. I might try it in my auto - I think some of the “myth busters” are putting out myths about smoking your transmission doing that- we never put it back into drive until we slowed down enough. And many of the articles talk only about gas and don’t say a word about your auto downshifting when you let off the gas down a slight hill thus braking and slowing you down. Even without a downshift you still have a transmission drag force that’s higher in gear than in neutral.

Update: @shakerhood After doing a little more reading I think you’re probably right about with modern vehicles having fuel injection and DFCO you probably won’t improve mpg by putting into neutral. I read somewhere that the transmission will upshift at some point after letting off the gas letting it coast better (I believe I’ve noticed this but need to pay more attention to what my truck does lol) yet other places I’ve read it downshifts -pretty sure I’ve observed both depending on conditions. I did find this link that was helpful to me to better understand when DFCO would cut fuel off and back on (though still not sure it cuts it totally off some conflicting info out there).
https://www.toyotaguru.us/engine-control-systems/deceleration-fuel-cut.html
And this post makes me want to test things out for myself:
https://www.tacomaworld.com/threads/off-throttle-slow-down.437074/#post-12661481

 

Good deal. Thanks for the explanation!

 

‘21 SR auto 4x4 V6. 25,000 miles. Stock except 17” Sema wheels and tires that are still stock sized.

14-15 mpg going 70-80 mph
15-17 mpg going 60-70 mph
17-19 mpg going 50-60 mph
20-20.5 mpg going 40-50 mph
All highway.

I once got 22 MPG going 40 mph on a flat surface over the course of 200 miles on a dark backroad.

I have also noticed that our trip computers are pretty damn accurate.

 

What will get messed up? Just curious as I have done this numerous times over the years and haven't seen any issues.

 

I've never left a vehicle running when filling up. Good way to loan your truck tom someone you don't know....thats just wrong.

 

It's also illegal in many states to leave your vehicle running while filling up. Lots of good reasons in here to not leave it running.

 

Not exactly. When you shut off the engine the gas builds up pressure and that’s what you hear when you remove the gas cap. While the fuel pump provides positive pressure to the fuel rail, the tank can be under positive or negative pressure depending on conditions and evap operation. Not going to destroy anything leaving it running with the cap off to fuel but I wouldn’t fuel up that way.
https://www.toyotanation.com/threads/gas-tank-under-pressure.366553/

For example if you have a faulty fuel cap gasket not sealing the fuel tank you’ll get a code:
“P0446 is normally not an immediate threat to the drive-ability of your vehicle. Certainly anytime the service engine soon light is on, it’s good to deal with it as soon as possible though. It is often accompanied by P0442. P0420 is another common trouble code that often accompanies P0446.”
Source:
https://www.700r4transmissionhq.com/p0446-toyota-tacoma/

 

Yep, if ya don't like a Taco's millage get a Corolla. The WORLD's best selling car.
Just think...a Corlla w/2" lift, some nice AT's and...Oh wait, that screws up millage again. Never mind.

Welcome to 2022

 

I generally get 21-22 mpg highway driving. I just moved halfway across the country, and got 12-13 mpg with a fully loaded truck, pulling a car trailer with a BMW on it. It did drop down to 8-9 mpg when crossing the blue mountains in Oregon, and the Rockies in Utah and Colorado.

This is a kbmax tuned truck with stock size AT tires.

 

LOL. its also illegal to drive over 35 on some roads to!

 

Been tracking my mpg on various vehicles for many years and I have noticed a consistent drop in mileage when the gas is changed to winter blend. (I'm in New England) Also a sharp increase in the spring when summer blend gets delivered.

It appears that different parts of the US have different regulations on gasoline blends so maybe this accounts for some apple-orange differences being reported here.

My results are my own and just an opinion.