My MPGs suck!

WrexHAmm

WrexHAmm

New member
I am going through my checklist and trying to improve my gas mileage. Only getting 15 around town, 16 mixed town/ highway. With MPGs like that I should have a V8 and not an underpowered V6.... but that's a dirrerent thread.

Here is what I have done:

Tires properly inflated
Changed air filter
Oil Change
Changed Spark Plugs
Put deckplate back in from deckplate mod
Clean MAF
Cleaned throttle body

Only mods that effect the MPG are the 265/75 tires but I was running them on my 01 and didn't have this problem.

Is my next step plug wires then O2 Sensors? I am hesitant to change the O2 sensors cause they are pretty pricey. Am I missing anything else that could be effecting it?
 
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WrexHAmm said:
I am going through my checklist and trying to improve my gas mileage. Only getting 15 around town, 16 mixed town/ highway. With MPGs like that I should have a V8 and not an underpowered V6.... but that's a dirrerent thread.

Here is what I have done:

Tires properly inflated
Changed air filter
Oil Change
Changed Spark Plugs
Put deckplate back in from deckplate mod
Clean MAF
Cleaned throttle body

Only mods that effect the MPG are the 265/75 tires but I was running them on my 01 and didn't have this problem.

Is my next step plug wires then O2 Sensors? I am hesitant to change the O2 sensors cause they are pretty pricey. Am I missing anything else that could be effecting it?
Click to expand...

Great thread!!!!
I'm having the same issue. I traded my 01 taco xc 4x4 with 33s for a stock 00 limited t4r. My taco go better mileage. I havent really got into any mods yet but this is a bit scary for me. My taco had 230k miles and my t4r has only 98k. Does anyone have thoughts or ideas? Other than just shear weight?
 
I would love to be even getting 15-16 around town and highway, i have never gotten over 14.5 on the highway unless i run a fuel additive, then that got me 14.8 pretty sad, average I'm looking at 13mpg i hate it, i really don't think there is much I or maybe you can even do, just from my experience, because when i was completely stock i got up to 23mpg on highway and like 19mpg around town, the day i put a 2" lift on the front and that same day installed my 265/75 i went down to 16mpg highway and 14mpg around town, and went down 2mpg more with a 1.5" increase in lift in the front and lifted rear and 295/70/17's

I to have thought about changing my O 2 sensor but like you said don't know if its really worth it unless I'm going to get 2mpg increase of fuel, i think my next mod is going to be a Sea foam treatment followed with new spark plugs, O 2 sensor, and hopefully that helps if not I'm stuck
 
you could try the wires- you've done everything i would have.. your right in the middle when it comes to mpgs though. I was getting 19-20 before I did my lift- now im getting 15-16 if i'm lucky.. While alot of people on here were only getting 14-17 stock- Honestly I wouldn't worry about anything else being wrong. If your cat or O2 sensors were bad enough to cause problems i would assume you'd throw a code.
 
I average 15.4 around town in my 2000 limited. I've tried stepping up the fuel but that didn't work. My next step is plugs and wires hopefully I can squeeze another 1 or 2 out.
 
you could try the wires- you've done everything i would have.. your right in the middle when it comes to mpgs though. I was getting 19-20 before I did my lift- now im getting 15-16 if i'm lucky.. While alot of people on here were only getting 14-17 stock- Honestly I wouldn't worry about anything else being wrong. If your cat or O2 sensors were bad enough to cause problems i would assume you'd throw a code.
Click to expand...

I was afraid of that. I expected to get the miles I do after my lift, not before. Just thinking what it will do once I put the lift on *shudders*. Thanks for the info.
 
Im getting 19mpg as I sit now. Definitly do a seafoam treatment, take that deckplate back off, lube the driveshaft, change diff/ transmission/ engine to synthetic fluids, switch to mid grade fuel.. thats all I can think of right now.
 
take your yakima rack off for a couple weeks and see how your mpg fairs. Every bit makes a different and the more wind resistance, the crappier the mileage.
 
I get 15-16 around town, but I just did 21 again, generally when all the parts are changed and it running right it boils down to driving characteristics.
 
A scangauge II tool helps with the lead foot, shows instantaneous and average MPG's.

Also, are you compensating for the larger tires when figuring fuel mileage?
 
Well there are 5 sensors that effect fuel trim:
1) Mass Air Flow Sensor
2) Engine Coolant Temp Sensor
3) Throttle Position Sensor
4) O2 sensor (x2)
5) Idle Air Control Valve

Make sure they are all in working order. It is good to get a diagnostics on there as well. I believe a CEL would come on if you were running in open loop mode.

Make sure your accessory pulley's are all turning freely.

Clean your MAF, IAC, Throttle body. Replace air filter, spark plugs, wires, run seafoam through intake manifold (PCV). And notice your whopping 1-2 mpg increase :D
 
Don't forget to factor in the ratio for larger tires. For example going from stock 265/70/16 to 285/75/16 tires there is ~7.3% difference so multiply what your odometer shows by 1.073 and that will give you a more accurate estimate of actual milage.

225 x 1.073 = 241.425
 
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change you front o2 sensor, toyota and denso say they are only good for 100k after that they start to crap out, just cause its not throwing a code dosent mean its not fouled. on top of that change your fuel filter, they are cheap less than $15 and easy to put in. change your plugs -with the correct split prong plugs, either denso or NGK, and change out your wires. if you want to get really meticulous then change all your fluids(oil, diffs, tranny and t-case) to synthetics. whats the load rating on your tires? if they are E rated tires they are heavy and gonna eat mileage. i have 285 70 17 E rated Bighorns, full armor and sliders(no bumpers yet) but i pull 16-18 depending on how i drive it, with a mix of city and hwy. but i try to be easy on it, when i drive it and am not trying to get good mileage then yeah i drop down to like 14-15. but all the things you have done i did plus the o2 and fuel filter. my last trip to cali to go camping and wheeling i tipped the scales at 5700+ lbs and i got 18 mpg averaging 70mph(sure i had my tires at 60psi, but again they are E rated tires and i was with in the recommended range)
 
You went with larger tires right?

It's kind of early to consider regearing, I think. But that's an option too. I would eliminate all the other options first though.
 
4-Ripcord said:
A scangauge II tool helps with the lead foot, shows instantaneous and average MPG's.

Also, are you compensating for the larger tires when figuring fuel mileage?
Click to expand...

Yeah, you have to compensate for the larger tires. I usually get 17/20. I just got 19.6 today with 25% city/75% highway. I found percentage difference between my odometer reading and actual distance traveled over about 150 miles I got a 7.57% difference. So you just multiply your odometer reading at fill up by 1.0757 to get actual distance traveled.

If you're compensating for over-sized tires and still getting bad mileage then maybe check: spark plug gap, resistances of the different sensors mentioned against the factory specs.

One thing you could do is monitor the air/fuel ratio (I'm not sure if the scangage can do this) and compare that with the a/f ratio of other 4runners getting reasonable mileage. If you're a/f ratio is low then I'd look at your sensors. If your a/f ratio is comparable to others then maybe there's some extra resistance in your drive train.
 
I got 98 auto 4x4 sr-5 4.10 gear, with 4'' lift front and 5'' lift rear and running 305-65-17 M/T ATZ tires, and get 16-17 MPG in city i get 230 mile with 14.5 gallon with stock odometer so 250 mile with GPS and on straight freeway no hill getting 290 mile or 310 mile with GPS with 14.5 gallon 21-22 mpg on highway, now just got Truetrac LSD for front and yukon Grizzly locker and 4:88 yukon gear still the same MPG or less 16mpg maybe it better later after it break in, Some how when i go trip said is 160 mile long and my truck only take 150 mile on odometer sorry for my spelling.
 
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