Terrible gas mileage

I bought my 2006 4Runner with oversized tires knowing the mileage would not be good but this is ridiculous. I am getting 12 MPG with regular gas. Any suggestions? The thing runs great other than the crappy MPG so hoping to learn something here as I just joined the forum.

 

12 seems low. I get 13 city, 16 highway, on a rig with 33 inch mud tires, a tube front bumper, full armor, fridge, heavy rear bumper, and a roof rack with a pair of Zarges boxes and a set of traction boards. 6000 pounds. Everything but a parachute.

I do keep the speed under 70 because economy takes a nose-dive at higher speeds. But that's with a high drag low speed build.

Perhaps your speedo is off due to the tire size, and you're under-reading the odometer and fuel economy?

 

What size tires? The bigger they are, the more they'll throw off the odometer.

What load range? LT tires will be heavier than SL tires. The heavier, the worse it will be.

How fast do you drive? How much highway VS city? The 4Runner will guzzle gas at higher speeds, and also with a lot of stop and go driving.

Which engine?

 

@Thatbassguy psi and alignment might also impact right?
4th gen also have 2 generations of V6 and 2 generations of V8 right? Don't remember the years they changed. I think the newer V8 is 2004 or something? And don't remember when the V6 got DVVTi.

And true exact tire size, load rating, make and model matters as in some sizes Load C is heavier than Load E in some make and models. Def can impact.

Also may be weight of the vehicle? Like you are on the heavier side for a purpose so can't complain on mpg.

 

Good points. I think the V8 went VVT-I in '04 or '05. I'm not sure if the 4th gen ever got the dual VVT-I 1GR.

 

I think you are correct. Only 5th gen got the DVVTI V6. I think only FJs had both.

 

Which engine do you have?

 

The tires are LT285 70 17's and it has a 4.0 motor. My mileage gets very little better on the highway. I keep it at the posted speed limits.

 

Lol. Put stock tires back on it, that seems like pretty normal fuel consumption.

 

My 08 V6 on 285/70’s, steel bumper, sliders, skid plates and spare tire carrier gets about 15 around town. 12 seems awful, might need a tune up?

I also have 3 degree retard cam gears and an intake plenum spacer so that helps a bit.

 

That mpg doesn't surprise me really. The V6 doesn't have the most power in the world. Those tires add a decent amount of weight. That affects the mpg. You have to ask yourself, Did I buy a4Runner for the gas mileage. You might get one or maybe two points from a cold air intake. Maybe

 

Trust me, I will as soon as these tires are worn. I bought it as is and the tires rub the fenders. My go to tires are Michelin LTX MS.

 

Clean your mass air flow sensor and throttle body. Make sure your air filter is clean.... then maybe try premium fuel for a tank or two and see if its worth it. Also make sure your tires are aired up(35psi is the sweet spot on my 4r with 285s.

 

My 06 4.0L developed a rough idle a few years back. Jay Leno's Garage said he runs Archoil, AR6200 in Every one of the cars in his collection. So I gave it a try and this cleared it up quickly. I can't even feel the engine running at idle with 249K miles. You could also buy the Archoil AR6400-G one time to do a quicker clean. Since finding this, I've at least run a bottle of the AR6400-G on every high-mileage car I touch.

 

12mpg is only 3mpg less than what I get on my 2019 4Runner when I get poor MPG. 12 sounds bad, but in the long history of trucks that's pretty good. lol

May need a tune-up though, and the large tires can definitely effect MPG.

 

im only on my second tank of gas - 13.7 steady - with stock all terrain tires

 

Filled my tank yesterday. 20.1 mpg. Zero highway miles.

 

wow...that's impressive - all season tires? i have a coworker that swears he gets 18 around town. i do have a pedal commander on it so i expected a bit lower - hoping maybe it will get a touch better after its broken in - only have 325miles on it

 

Down hill with a back wind. lol

After I broke in my 4R i was able to get ~20mpg at slower speeds around town in areas like VA and NC. Now with my 10min commute and super short stop and go in CT its more like 15mpg.

 

I ordered the AR6400-G. Thanks!!! Probably like Klotz which I have already tried but I will give it a whirl.

 

Intrigued, ordered some archoil as well. Will give it a go.

many difference over using Seafoam in the crank case or fuel tank?

 

I seem to recall my mileage improving after a few thousand miles.

It seems like the biggest enemies are stop and go traffic, high-speed driving, cold weather, and high elevation. Any combination of those will hurt your mileage.

When mine was fairly stock, I could get over 20 pretty regularly on the highway (~60-70 MPH).

 

I'm running LT285/70R17 on my 5th gen. They were on there when I bought it. Any idea what PSI I should have them at? I was loosing PSI every 4 days, found out the shitbag Toyota Mechanic loosened my valve core a half turn on all four tires. So stay away from Sun Toyota in Florida.

 

Based on the calculator, those should be run at 38. This is a good way to figure out the safe PSI based on size and load range.


A lot of folks will do a "chalk test" to decide what pressure to run, also.

 

I don't have anything special loaded. It has a 3" lift and the standard skid plates and sliders. I'm assuming that is 38 PSI cold?

 

Bought this rig from a kid that works at a Discount Tire. I will always buy Michelin LTX MS tires.

 

Yes, cold.

 

Nobody ever says, but differential and transfer case oil make a difference on MPG. Change to sintetyc oil with manufacturer specification.
Make sure too you are using the right engine oil viscosity 5W30.

 

The first and all future oil changes are Mobil One 5W30. The previous owner said he used a synthetic blend.

 

Stock 2020 ORP here. Running stock sized Geolanders P-Metrics. Mobil 1 0W-40 oil. Last tank was 18.3, mix of town and open road at 55ish. Open road at 55ish is usually 21-22, and freeway at 70ish is 19.5-20.