I am at my wits end with this 91 3.0 4runners mileage.Once it gets down to 1/4 tank of gas,and I drive it to work,12 miles from home,it is just above empty.It had a tune up and all the injector seals have been replaced,and one injector.My next step is to replace the o2 sensor and cat.It runs good with no black smoke.What else could it be?

 

I think it might also be the o2 sensor...my buddy had a problem with his s10...it was dumpin fuel and gettin really bad gas mileage. He got it fixed and he has no more problems.

 

Your gauge? Mine sort-a does the same thing. It flies down the first half, then takes forever to go down the second. I also have never run out of gas and the needle will be touching the E way after the gas light has come on and gone back off its so low Thats crazy though. Are you leaking anywhere?

 

Either you are leaking or the gauge is screwed up.
That much gas would be very obvious (in a leak or in massive amounts of black smoke)

 

Mine's the opposite, barely moves for the first half, and then goes from 1/4 to 0 almost instantly. Check you mileage for a full tank, not just the last 1/4.

 

Nope,not leaking.It doesn't smoke at all.It's like I can almost watch the gauge go down.I usually hit 115 ish miles on the odometer at half a tank and then when it's on e the mileage is at 215-230.My 87 with 22re and 33's with stock gearing gets better mpg's,my v8 trans am gets about 20 mpg's. I know the 3.0's aren't veray economical but it should be better than that.

 

The guage may not be reading linear. Instead of thinking that you have bad gas mileage, do a gas mileage test. Fill the tank, drive until almost empty, then divide how many miles you drove into how many gallons it takes to fill your next tank of gas.

 

I've been driving my 1990 4 runner with the 3.0L for the past 7 years
No matter what - 225 miles to the tankful.

 

with my 33's and auto tranny im lucky to get 185 miles to a tank

 

The dude never says how much it then takes to fill it up.

My 95 will read well off the gauge before it is bone dry.

If you go from 1/4 to E in 12 miles and then it takes a full tank, something is wrong.

 

That's wierd too bacause I thought they had 18 gallon tanks and when I fill it up it usually takes between 14 and 15.I almost want to keep a gas can in it and run it out of gas.I know it's not good for it but I'm stumped.

 

There is nothing wrong with your truck.
Mine will do 200+ miles from full to 1/4, then a few miles the rest of the way down. When it's at E i usually still have 7-10 litres in the tank.
Basically, the guage is not linear, it's degressive (the opposite of progressive) because it's old.

 

i usally have 3-4 gallons left when the empty light goes on.

 

Running 33's here and get about 205 to the tankfull. From full to 1/2 tank it reads about 120 miles, from 1/2 to 1/4 tank about 185 miles, the light comes on at 205 miles. So I don't think it's your gas mileage, it's just the way gauge is reading it. If it was an indication of mileage I should be getting about 250 miles to a tank. I wish!

 

My gauge is flakey - similar but not that bad.

 

im with greg, mine does the same thing. jed, you probably should take a spare tank with you some time. fill up and drive until its sputtering, dump in the spare can and do the math. that will tell you what your actual mileage is. drive as you would on a regular week, that will give you a good idea. mine gets around 400-450 kms per tank in the city and 550-600 kms on the highway.

 

99% of all gas gauges do that, although maybe not quite as pronounced. They aren't linear. Mine for example will go 90 miles between fill up and the full mark. The first half goes down much more slowly than the second half. This is true of every car I've ever owned.

Also, even if you have an 18 gallon tank, you can never really get it full (there's a built-in air space at the top) and there's usually still a bit left when you hit the E mark. If it bugs you, run it out of gas, then pull the cluster, pull the needle and reseat it at the E mark.