BigSquatch

my mpg has gone horrrribly low. Stock 00 limited 4wd, 60k miles. I used to get at least 200+ a tank, now ill be lucky to get 150!!!!! i would say im at 100 miles and just a little above 1/4 tank left WTF!! i drive like an old man too, no lead footing whatsoever. Pretty much all city driving no highway.

Only changes ive made is to full synthetic. Doesnt seem to be running rich, no black tailpipe, no nothing. my first instinct after doing some reading is to replace the front oxygen sensor, even tho im not getting a code. Just seems like since it started getting cold my mpg just hit a brick wall. Im crapping my pants here cuz i havent really heard anyone getting below 200 miles to a tank.
everyone is going to say do a tuneup which i agree would prolly couldnt hurt. the truck is all up to date on matenance (dealer) as well.

mikes19984x4

how is it running right now? any loss of acceleration, hesitation, etc?

MadCityRich

It's important that you track your actual mpg and not "miles to a tank." To do that, start with a full tank. Record your miles from the odometer. Drive as you would, but when you go to fill up again, record the miles again and figure out how many miles you've driven since the prior fill up (or just use your trip computer). Then divide the miles you drove by the gallons you just purchased. That gets you mpg. Track it over time and you will see trends.

This will tell you if you are really getting bad gas mileage or if your sending unit is wacky.

I always see a big hit in winter with gas mileage. The winter blends of gas tend to give worse mileage, cold weather can really hurt mileage, and I tend to make more short trips.

Hope this helps,
MadCityRich

Ian Rogers

i see a drop in the winter as well, i dropped from 20.5 adv to 18.5 adv. What can you do, i am going to S/C my truck and hope that helps lol...

Texas_Ace

Part of the reason that you are seeing lower MPG's when it is cloder is that when air is colder it gets denser. Did you know that by just lowering the air temprture you can increase HP by 10%+? And on a FI engine even more.

So more air in engine = more gas needed to burn it. Which is why the MPG's go down in the winter but your power gets better.

Here in Texas right now it is 30 degrees at night but 75 in the day today. When i drove this morning my truck was nice a peppy but in teh afternoon it felt more normal. It is amazing how air tempreture can affect the power so much!

BigSquatch

nope seems to be running great.

infiltrator

its probably the winter gas. im noticing a big change like you are. i used to get a good steady 100 miles to a half tank (hey im not rich lol) but now its down to about 65! maybe 70!

winter gas is different. plus theres like condensation i think in those tanks that hold gas underneigth. so your getting watery gas lol.

rearviewmirror

Info on tracking your economy here.... https://www.yotatech.com/forums/f2/w...runners-86034/

I've got almost the same setup as you, a 2000 4WD Limited w/ 54k miles running full synthetic. My fuel economy has always sucked, but I keep her pretty loaded down with gear. I average 15-18MPG. Check out that thread above.

AppleJack

When did you notice you mileage losses?? Some areas don't use winter grade gasoline but my area does and I always get worse mileage with it.

BigSquatch

a few weeks ago, we definately have winter blend gas here. i dunno i didnt think itd make that big of difference dang..

mikes19984x4

yep, like everyone is saying, the winter gas will definitely do it...i notice a large drop in mpg when doing mostly city driving in the winter, but it seems like my highway mpg in the winter will drop at most 1.5 mpg, so i'm still getting above 20mpg for those long trips...

mt_goat

That does sound abnormally bad. How much does that BigSquatch guy weight, maybe quit hauling him around

Yeah might try replacing the front O2 sensor, cleaning the MAF, cleaning the fuel injectors or having them tested (maybe one is leaking or something) Do you park in a garage? It makes fuel leaks easy to notice when you park in an enclosed area.

MillerPKA

i took a trip up to atlanta the other week and got 10 mpg going up there! But oddly enough, 12 hours later coming back i got 18. what gives?

Texas_Ace

The tempreture?

mikes19984x4

going uphill most of the trip up? and, as odd as it sounds, depending on how strong of a wind there was that day and if you were driving into it, that may affect your mpg...just a thought

metalhed

I have similar problems with my 01 Tacoma, winter gas, short drive to work (2 miles). I am thinking about replacing the front O2 sensor. Is it worth changing the rear O2 sensor at the same time. I am going to replace the fuel filter and the O2 sensor and hope this help improve the MPG.

Toyvana

If you are running heat using the climate control, does that lower gas mileage? I understand using A/C will kill mileage but does using heat have the same result?

mt_goat

Nope, only change it if you get a code. All it does is let the ECU know if the cat is working good enough.

BigSquatch

would a fuel injector leak cause a CEL?? no i park outside but i keep a very close eye on any leaks, none as of yet. But then again fuel does tend to evaporate.

man i dont feel like crawling under the truck in this freakin weather, im sure that o2 sensor is welded on there with rust. fun fun fun.

FYI sasquatches weigh approx 250 to 800 lbs. food for thought.

cackalak han

You should check the spark plugs, just in case. Also, my old 98 4Runner had problems with the fuel gauge where it would read wrong at times. When you're filling up at 1/4 tank, how much actually goes in? Follow the instructions that MadCityRich posted and report back. I don't know why people go off about "miles per tank" as it is almost useless info. People need to realize that the fuel guage is NOT always correct.