21.7 mpg with bumpers and rack, but...

[Thurlo76]

right after i got my 97' 4runner i took some friends to spokane washington from moscow idaho. i think it was around 168 miles round trip and pretty flat. i got an honest 23 mpg and i was shocked. i then drove from moscow idaho to ontario oregon and i made it all the way back (225 ish miles) on about 5/8 of a tank. and averaged 21mpg. i also had pretty wore down 265/70/16's.

I got home the only things i have done are replaced the stock muffler (old one had started to split and rust through) at a shop with a new "stock" one, put new 265/75/16's A/T's on, installed a tow package, and did a sea foam treatment. After that the best i have got is 19mpg. WTF??? going to head over to the oregon coast in a few days and im going to set my cruise at 57mph the whole time and see what happens. I will change my oil, do a deckplate mod, and do the big 3 upgrade (because my wires are very brittle) when i am over there and i will see what happens on my way back home.

cant figure out how i dropped that much. these are honest numbers btw if anyone thinks im full of sh**

 

[Grenvilleter]

Aside from a properly tuned engine, the biggest contributor on a stock vehicle's gas mileage or lack of it is the interface between the throttle and the steering wheel.

I make it a point to check mpg's every fill up as once a baseline is set, it can be a very reliable method to access the overall health of your drive train or more importantly, if a change has taken place. Finding the cause of a sudden drop can prove to be more difficult

A sudden avg drop in mpg could mean anything from failing to grease your drive shaft to improper tire inflation and a hundred other things including ambient outdoor air temperature.

I think the sweet spot for best mpg is just at the point where the truck shifts into OD at ~50 mph. I have a tough time keeping my speed at this mark however.

 

[02running]

i drove from richmond, va to long island new york on my 285/75/16 at 2's and got 21.9 mpg according to my recently calibrated ultra gauge. cruise control and pretty flat driving helped a lot.

 

[T4Rscott]

I would be careful drafting a semi. The tires on most trailers are re-caps and they will separate without notice. I am speaking from experience here, most memorable was on 95 south bound in Peabody Mass, just before I got to Rt 1, the cap came off a tire and landed on the hood and windshield of a Cadillac DTS. So please be careful! Those caps are heavier than the look and do a lot of damage.

Scott

 

[Grenvilleter]

It's difficult to get numbers that are 22+ mpg but very possible. Geographic location/season plays a huge roll in consumption.

The gas you use even (% ethanol added) plays a significant part.

Then there is the "rolling" resistance factor that depends on tires, ground height (wind).
If your not getting that kind of mileage, I suspect it's because of higher drag from wide tires, lifted body, additional weight overall compared to a stock vehicle.
You should not however make assumptions that these numbers are downright impossible to get.