I know, another Poor gas mileage thread.

[m85476585]

If your driving involves a lot of traffic lights and stop signs and short trips, then 16mpg is good. On the highway MPG depends on your speed. At 65mph you might be able to get 20 from a newer V6, but at 80mph you will get more like 18-19 in my experience. For a newer V8 it's more like 18 at 65mph and around 16 at 80-85mph from what I've seen. The older ones without VVT-i are less efficient. Cold weather decreases MPG, as does winter gas.

I've seen the display show over 27mpg for a short trip. There's no way that's possible.

Anything restricting airflow to the engine shouldn't affect MPG. The throttle is the biggest restriction, and if for example the air filter is extremely dirty then the throttle just needs to open a little more to get the same airflow. The MAF and O2 sensors will make sure the fuel to air ratio is correct.

Some vehicles will open the throttle all the way and adjust the valve timing at low power output, in which case airflow restrictions may decrease MPG, but as far as I know our engines don't do that. I think some Hondas do that.

I suspect the rear spoilers decrease MPG, but keeping the rear windshield clean is a nice benefit, plus I think removing it leaves holes in the body and no third brake light.

Extra weight will decrease city MPG, but it shouldn't affect highway MPG much.

At lower speeds the torque converter in the transmission won't lock up, so it's less efficient. I think it locks up over 45mph, generally.

Bad alignment could affect MPG.

My mileage has been slightly lower than expected recently, but with gas being so cheap I've been driving with no regard to efficiency. Might as well take advantage of the V8!

Here's my fuelly if anyone is interested: 4runner (Toyota 4Runner) | Fuelly

 

[heiser]

Side note: We know the lie-o-meter is useless for mpg, but has anyone found it to be accurate for the range of miles left?

 

[m85476585]

Side note: We know the lie-o-meter is useless for mpg, but has anyone found it to be accurate for the range of miles left?

It is not always accurate for range. If your mileage is inconsistent it will not give you a good idea of range. If you always get the same mileage it seems to be reasonably accurate. If you idle overnight it gets confused about how much fuel is left until you drive around. And if you hit 0 miles you don't immediately run out of gas.

The most consistent thing I've found is that the low fuel light comes on around 20 gallons used, so there is still a bit left in the tank.

 

[fdbyrne]

Side note: We know the lie-o-meter is useless for mpg, but has anyone found it to be accurate for the range of miles left?

The lie-o-meter is actually more useful than you think. In my experience, it's always wrong but since it's always wrong the same amount it's still easy to read. Mine is always 2.0 or 2.1 mpg higher than actual with no real variation. That's over the course of the year and a half that I've owned the truck.

Mine usually reads about 18.1 in the winter and about 19 in the summer. I calculate the actual mileage at every fill up because I'm OCD and the real numbers are about 16.1 winter and 17 summer.

 

[mizak82]

so basically 16.1 for the V6 combined highway/city is considered normal?

 

[fdbyrne]

so basically 16.1 for the V6 combined highway/city is considered normal?

It is normal for me during the winter. My 4Runner is stock and I drive like a grandmother. It does have 140k miles on it so maybe it doesn't get as good compression as it used to and has to work harder, I really don't know. I've only had it for year and a half.

My commute is about 11 miles, takes about 20 minutes, and is about 50/50 highway and city.

 

[heiser]

The lie-o-meter is actually more useful than you think. In my experience, it's always wrong but since it's always wrong the same amount it's still easy to read. Mine is always 2.0 or 2.1 mpg higher than actual with no real variation. That's over the course of the year and a half that I've owned the truck.

Mine usually reads about 18.1 in the winter and about 19 in the summer. I calculate the actual mileage at every fill up because I'm OCD and the real numbers are about 16.1 winter and 17 summer.

I've noticed that too actually. Mine is usually 1 to 1.5 mpg higher.

 

[Roadtripr]

It is not always accurate for range. If your mileage is inconsistent it will not give you a good idea of range. If you always get the same mileage it seems to be reasonably accurate. If you idle overnight it gets confused about how much fuel is left until you drive around. And if you hit 0 miles you don't immediately run out of gas.

The most consistent thing I've found is that the low fuel light comes on around 20 gallons used, so there is still a bit left in the tank.

Yea like 3 gallons....
I only start looking at my trip odometer if the light comes on. If I drive like normal I got 45miles left while the range is saying 0

The average mpg is always off (too high). 16mpg with mixed town and hwy is normal. I only get better if i drive around 60-65mph. Stop and go or >70mph and it drops. Unlike my old 3rd gen the 4th gen actually gets up and goes but burns some more fuel to do so

 

[asdfman7]

Commuting 40 miles a day round trip to and from Seattle, keeping it under 70 when not stuck in traffic, I average 17.5 using premium and 16.5 with regular, the display reading 19.1.

Imo, one possible reason that the computer is off on calculating mpgs is tire size. Most of us run a slightly bigger tire than the computer was programmed for. I'm sure that's not the only reason but it could make a difference.

 

[Billynath1988]

Nah the computer was off even when I was bone stock. But those ^^ are the numbers I used to get. I found the biggest culprit to MPG loss for me on the v8 was lazy calipers. Not necessarily sticking all the time but not functioning properly. Im about to order 5th gen front calipers this time around.

I have doen every fluid change and tune up you can do.. After changing original front calipers to new ones I went from 13-14 mpg to avg of 17-18

2 years later for absolutely no reason im back to 13.. The only suspect left is lazy calipers. Even with larger tires and armor.. my highway mpg was barely affected at all maybe 1mpg until recently.

 

[heiser]

Nah the computer was off even when I was bone stock. But those ^^ are the numbers I used to get. I found the biggest culprit to MPG loss for me on the v8 was lazy calipers. Not necessarily sticking all the time but not functioning properly. Im about to order 5th gen front calipers this time around.

I have doen every fluid change and tune up you can do.. After changing original front calipers to new ones I went from 13-14 mpg to avg of 17-18

2 years later for absolutely no reason im back to 13.. The only suspect left is lazy calipers. Even with larger tires and armor.. my highway mpg was barely affected at all maybe 1mpg until recently.

Makes me wonder. I checked my calipers last night after driving. Neither was abnormally hot, but they might not be 100%. Who knows.

 

[B33R_Runner]

so basically 16.1 for the V6 combined highway/city is considered normal?

16.1 mpg seems low to me for the V6. Here's my experience, FWIW: I drive an '03 SR5 4WD with 268K+ miles on the odo and stock-sized Michelin LTX M/S2 tires. It has a current calculated average of 18.77 mpg. Granted, I've only been calculating it for the last ~8K miles, but I believe "what have you done for me lately" applies here. This average does include quite of bit of highway miles, but many of those were at 80+ mph and loaded down with luggage and camping gear. Rest is city traffic in Houston (not exactly efficient-friendly). I have no actual proof, but 45 mph to 65 mph seems to be the sweet spot for me. My best tank in the past 8K miles was 21.0 mpg, and my worst was 14.1 mpg (a small fill up after some off road miles). As for the on-board display, I reset mine on a monthly basis for comparison. :nerd: In the last year, my lowest month was 19.7 mpg and highest was 22.7 mpg -- consistent with the +~2 mpg higher than actual calculation that others experience.

I'm pretty happy with those results so far. If maintenance is up to date and everything is mechanically sound, then personal driving style is the next factor to examine. For me, I'm easy on the go pedal, and I tend to slow down early. :second: People love to rush to red lights! Occasionally, I downshift to 3rd (only four gears in the '03) to help slow down. I also don't have a ton of crap in the cargo area. Removed the pointless (for me) running boards.

Cover all the bases even if they sound like obvious questions. Are you using highway tires? Are you carrying unnecessary weight? Do you drive with MPG in mind? Alignment good? How much of your daily trips is the 4Runner actually warmed up completely? Throwing things out there. :beer:

 

[jrm]

Does the 4th gen have the same tank as the 3rd gen?

that includes a baffle in lower 3rd of the tank which traps two gallons of fuel below the fuel pick up in the case the trucks axis changes so the pick up doesn't suck air in the FI system?

This would help to explain why the average MPG readout is higher than actual MPG b/c the readout thinks you have 22 gallons of fuel when you only have 20 gallons.

The 3rd gen fuel gauge inaccuracy caught me running out of gas a couple of times before i bought a ultragauge for a more accurate reading but still was never "right on" when it came to reading how much range i had.

 

[fdbyrne]

16.1 mpg seems low to me for the V6. Here's my experience, FWIW: I drive an '03 SR5 4WD with 268K+ miles on the odo and stock-sized Michelin LTX M/S2 tires. It has a current calculated average of 18.77 mpg. Granted, I've only been calculating it for the last ~8K miles, but I believe "what have you done for me lately" applies here. This average does include quite of bit of highway miles, but many of those were at 80+ mph and loaded down with luggage and camping gear. Rest is city traffic in Houston (not exactly efficient-friendly). I have no actual proof, but 45 mph to 65 mph seems to be the sweet spot for me. My best tank in the past 8K miles was 21.0 mpg, and my worst was 14.1 mpg (a small fill up after some off road miles). As for the on-board display, I reset mine on a monthly basis for comparison. :nerd: In the last year, my lowest month was 19.7 mpg and highest was 22.7 mpg -- consistent with the +~2 mpg higher than actual calculation that others experience.

I'm pretty happy with those results so far. If maintenance is up to date and everything is mechanically sound, then personal driving style is the next factor to examine. For me, I'm easy on the go pedal, and I tend to slow down early. :second: People love to rush to red lights! Occasionally, I downshift to 3rd (only four gears in the '03) to help slow down. I also don't have a ton of crap in the cargo area. Removed the pointless (for me) running boards.

Cover all the bases even if they sound like obvious questions. Are you using highway tires? Are you carrying unnecessary weight? Do you drive with MPG in mind? Alignment good? How much of your daily trips is the 4Runner actually warmed up completely? Throwing things out there. :beer:

There are probably other factors at play, but some of the difference is probably due to the weather up here. People are quick to point out that winter gas gives worse gas mileage but I think that the cold itself is a bigger factor. During the winter I spend much more of my commute with the vehicle below it's normal operating temperature. Sometimes I'm a few miles down the highway before it completely warms up.

During the rest of the year it warms up almost immediately and I'm running at peak efficiency for more of my daily commute.

There could also be a difference in the gas itself between Missouri and Texas. The highest MPG that I ever got off a full tank was from gas that I purchased in Dallas. It was all highway from Dallas to Springfield, MO and when I filled up and did the math I'd averaged just shy of 21 mpg. If I remember right, I noticed a sign on the Dallas pump that said that it was 100% gasoline with no ethanol. Around here, everything is blended.

 

[B33R_Runner]

There are probably other factors at play, but some of the difference is probably due to the weather up here. People are quick to point out that winter gas gives worse gas mileage but I think that the cold itself is a bigger factor. During the winter I spend much more of my commute with the vehicle below it's normal operating temperature. Sometimes I'm a few miles down the highway before it completely warms up.

During the rest of the year it warms up almost immediately and I'm running at peak efficiency for more of my daily commute.

There could also be a difference in the gas itself between Missouri and Texas. The highest MPG that I ever got off a full tank was from gas that I purchased in Dallas. It was all highway from Dallas to Springfield, MO and when I filled up and did the math I'd averaged just shy of 21 mpg. If I remember right, I noticed a sign on the Dallas pump that said that it was 100% gasoline with no ethanol. Around here, everything is blended.

The weather and the topography (can you say flat?) probably do help me here. No 100% gas here, though. EPA mandate for Harris and surrounding counties.

 

[mizak82]

im from south florida its flat and warm.. def not that..

I figured I would get 18-18.5 with the car mix mileage when I bought it..


no brakes were hot..


could be the plugs i got.. they were denso iridium power.. very small electrode on the spark plug.. look like a pen tip.. but they were the top of the line plugs.. and they were out of NGK..

 

[tmcintosh3]

Stock, I was at 19/20. Now, with lift/bigger tires and roof rack, I'm at 13.9/14 mpg. When I put the spare tire on the roof...forget about it, I go down to about 11.

Interested to see what I end up getting once I put on some 35s! :flame:

 

[m85476585]

The weather and the topography (can you say flat?) probably do help me here. No 100% gas here, though. EPA mandate for Harris and surrounding counties.

The extra energy in 100% gas is in the noise compared to 10% ethanol gas. It looks like it's less than 2% different. https://en.wikipedia.org/wiki/Gasoline_gallon_equivalent
I tried it once in my last car and it made no noticeable difference. with 100% gas you might get 18.36 mpg instead of 18 mpg.

 

[heiser]

Now I'm really getting worried. My last tank was 13.8mpg, mostly city. 2.5/1.5 lift and stock tires. It really shouldn't be that bad...

 

[dkyleb]

Now I'm really getting worried. My last tank was 13.8mpg, mostly city. 2.5/1.5 lift and stock tires. It really shouldn't be that bad...

Clean MAF, clean throttle body, unplug battery for 20min. Drive a few tanks, see if it improves. If not, replace O2 sensors.