How to improve your mpg?

[bdg4512]

I have changed out my spark plugs, changed diff fluids, O2 sensors, and put in a True Flow air filter, and only use 93 octane gas, but even though I am very easy on the gas, I can't break 16 mpg. Even on the Highway. Does anybody have any ideas as to what I can do to improve the choke hold gas prices have on my wallet?

Thanks in advance guys!

[Cebby]

How much air are you running in your tires? Did you change to synth in the diffs? What about synth fluids throughout? How about injector cleaner? How about a Seafoam treatment? Just a few ideas...

Loose the rack up top for at least 1 mpg.

[MTL_4runner]

I have changed out my spark plugs, changed diff fluids, O2 sensors, and put in a True Flow air filter, and only use 93 octane gas, but even though I am very easy on the gas, I can't break 16 mpg. Even on the Highway. Does anybody have any ideas as to what I can do to improve the choke hold gas prices have on my wallet?

Ben, first thing is that there is no need to be using 93 gas so don't bother putting in any higher than 87, you're wasting money if it's a N/A vehicle.

Other items....
1) Tires and tire pressure is another (make sure your pressure is set to 35 psi at all times for best MPG).
2) Roof rack will definately hurt mileage too (perhaps even more than 1 MPG).
3) Clean your MAF sensor (with brake cleaner) and pull the neg batt cable for 5 min
4) Change your fuel filter
5) Run your gas tank down to 1/4 full, add 2-3 cans of Seafoam and drive until the empty light comes on.
6) Make sure your vehicle is aligned properly (should have less than 1 degree of toe in/out)
7) Run synthetic fluids (I noticed a decent MPG improvement just switching to Valvoline Synpower engine oil and will be doing my diffs next)
8) Lube all driveline zerk fittings (driveshaft, u-joints, etc)
9) Tranny flush may help to some degree as well
10) Make sure your brakes are in good shape and aren't dragging (both front and back)

I'm sure we can come up with more but start with that list and see how you do. Also don't forget your tires are larger than stock so your going 3.4% farther than the odometer shows. Make sure your also checking your mileage correctly (fill up, reset odo, drive, refill and divide gal on pump by miles on odometer and multiply by 1.034....I've seen all sorts of crazy calcs from people, but that's how it should be done).

[mkgarrison5]

why do you multiply by the 1.034? just curious.

also about your plugs, make sure they are same as the factory installed ones. probably denso and or ngk. i have seen people run bosch, champion and a few others and they wonder why it doesnt run as good.

check your pcv valve also, if you havent changed it in a while, change it! its only a few bucks and it helps keep your oil in good shape..

[MTL_4runner]

why do you multiply by the 1.034? just curious.

Only in his case because he's running 265/75R16's which are 3.4% larger in circumference.
Therefore to account for it in the fuel economy, you multiply by 1.034

[MTL_4runner]

also about your plugs, make sure they are same as the factory installed ones. probably denso and or ngk. i have seen people run bosch, champion and a few others and they wonder why it doesnt run as good.

Excellent point!

Ben, what brand were the parts you put in (both plugs and O2 sensor)? Were they OEM?
If not, that may be part of your issue too.

[bdg4512]

THanks for all of your input, I have changed the tranny fluid, changed the diff fluids, gave the old girl a full Sea Foam treatment, I run 35 psi in the tires, and I used NGK Iridium plugs with a Denso O2 front sensor and put in a toyota fuel filter. All of this has been done in the last 6 months. I will try to clean the MAF sensor and lube all the fittings tomorrow and see where that goes. In the meantime, thanks again and any more help is greatly appreciated. Also I checked my speedometer with a navigation unit and according to the TomTom, my gauge is spot on. So does that mean the odometer is reading correctly too?

[randver]

you guys keep talking about taking off the roof rack. do you mean the factory one,and/or after market ones?

[firebane]

93 octane? Uneeded
Roofrack? Meh doubt it makes that much different.
NGK Iridium? Bad choice, get OEM.

[bdg4512]

They were talking about my Thule Basket, it's kinda like haulin a small shed on top of your truck, but looks cool! I'll change out the plugs tomorrow when I'm wrenchin on her.

THanks again!