So I bought this runner about 6mths ago with plans to make it a camping/trail rig I got some money into it and all that good stuff now. Im totally realizing that i get like 12.5 mpg avg.. I do kinda a lot of city drive but still it sounds outragous. I might as well be driving a 77 cadilliac with a big block. Could there be somthing wrong. I do have jardire exhausat and deckplate mod but thats it as in engine. Thanks in advance

 

bad 02 sensor??
dirty air filter??
bad fuel filter???
dirrty MAF sensor???
incorrect tire pressure???

 

Correct calculation?

 

I changed fuel filter air filter... What am i not worth my calculation haha... 210 miles on a full tank i get.. I will check MAF and 02 today.. thanks for the posts guys!!

 

Fill up, reset the trip meter. Run it close to E. Divide gallons used by total miles traveled. Repeat 3X (at least), calculate average.

 

The calculation should be done:
(mileage @ this fillup - mileage @ last fillup) / (gal of gas @ this fillup)

Repeat for more accuracy.

 

Make sure you use the gallons at fill up, b/c a lot of the 4Runner gas gauges are not accurate, such as mine, and will read empty and still have 4-5 gallons in them.

 

How amny gallons are you filling up with? Sometimes I only get a little over 210 a tank but I only can squeeze in 15 gallons at fillup so that's more like at least 14mpg.

 

I would bet on a dirty MAF. You are right My low fuel light comes on and I drive 30-40 more miles. I start to get nervious about running out of gas, it only takes 15 -15.5 gals. The tank on a 2000 is 18.4 gals. I get 20 -21 MPG on my 2000 even when pulling a trailer up the mountains I still get 19 mpg. I just did a trip to SLC and back with 4 adults, the back full and a hitch carrier full and got 20 mpg. At 12.5 mpg you have something wrong.

 

Be sure you do the calc like MTL_4Runner said, fill-up to fill-up. Forget the PER TANK crap. You want per gallon, and the calculation works whether you put 4 gallons or 14 gallons in...

 

I bought a 97 4runner about 2 months ago and have the same problem.
I need a tune up and hope that will help! it sucks!

 

I get 16 in the city and I thought that was bad.

 

Actually I've been getting over 230 a tank lately (I think tire pressure was low before) and only getting 14 gallons in when I think it's empty so I'm up just over 16mpg which I can deal with.

 

Tire pressure is a biggy with fuel economy.....about 1 psi lost for every 10 degree drop.

 

Im getting about 15 to 17 mpg right now. On long freeway trips its closer to 19. I recently did the fuel filter so I hope it goes up a little more (fingers crossed).

When I got the truck the mpg was bad but it improved after running an injector cleaner, changing the plugs, wires and air filter. Cleaning the MAF is next and the O2 is dead last on my list.

 

is there much of a diff between the 3.4L in gen2 vs gen3?

seems like the gen2's get worse MPG.

im stock and get 300mi+ b4 the idiot light comes on, never had below 18mpg

 

2nd gen Runners have a 3.0 and it generally gets worse gas mileage and has 30 less ponies so you get kicked in the nuts twice.

 

Don't forget to count any discrepancies with over sized tires... my 33's have my numbers (both speedo and odo) off by about 18%, and consequently, my mpg figures as well. Even so, my gen1 3.0 (lifted with the 33's) only gets 14mpg, my old gen1 with stock tires gets 17mpg, and my gen2 3.0 got 15 before the thrown rod.

 

yah, if you have 285s (metric 33"s) and your old size was a metric 31" - you need to multiply by 1.072 to get your "true" gas mileage. It might be better than you think!

aaron

 

14.5 mpg here on a stock 99 4Runner 4x4 manual. I think my tire pressure is messed up though. Hopefully it will be better once it gets warmer