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Discussion Starter #1
Hi there,

I hope you can give me a piece of advice to improve my fuel economy in my 07 FJ Cruiser 4WD A/T Base, I'm struggling with its 12-14 mpg each time that I hit the road. I bought this truck for camping trips, long drives, 300, 500, 800, 1000 miles and it's killing me.

I've installed:

A set of 33 in mud terrain tires (I'll replace them for a 33-in Toyo Open Country AT III),
TRD performance air intake,
AFE throttle body spacer,
AFE 3 in exhaust system,
New spark plugs,
Cleaned MAF sensor,
Clean O2 sensors,
Changed CAM position sensor,

Even though it has improved on performance and torque, I still can see the fuel economy is bad, I'd say 14 mpg. I'm planning to regear it, probably with a 3.91 gear set for my 33 in wheelset but I was told that a 4.56 one is what I need.

What would you recommend?
 

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What mods have you put on it?

Winter also drops mpg hugely.... with the warming up of the vehicle... fast idle at startup... winter blend gas... it all adds up
 
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14'FJ, Bilstein 6112/5160, SPC UCA's, Spod BantamX, 285 70 Toyo AT3, just getting started ;)
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Gas mileage shock w the FJ was a real thing for me. Ive owned it a bit over 2 months now and recently put Toyo AT3's on 285 70 17 and 2.5 inch lift. No bofy armor.

I drove 350 miles to Buffalo last Thursday and my gas light came on after traveling 190 miles! I was like...WTF!

After all the reading I did over the weekend i realized there's little i could do. Apparently i sacrificed some MPG's for mods.

I decided today ( as we speak) to test out changing my driving a bit. I'm literally on my way back from Buffalo now. Same 350 mile trip and made one simple change. Set the cruise a tick under 70, kept the rpm's just below 2k and my check engine light didnt come until 248!! That's almost 4 mpg's just from changing my cruising rate from 75 to 69.

It's not a home run by any meand but I'm definitely happy to know that my driving habits can improve my mileage. I took a pic today the second my light came on, showing my trip mileage.
 

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14'FJ, Bilstein 6112/5160, SPC UCA's, Spod BantamX, 285 70 Toyo AT3, just getting started ;)
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How hard are you on the accelerator?
What speed are you driving at?
Not hard....highway driving. Cruise control at 69 acoording to waze. Truly made a big difference.

Do I like driving at 69......no, not really. But I like it more then watching my fuel needle fall like a lead weight.

Just nice ( for me ) to know that when i feel like it I can improve my mileage.
 

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Discussion Starter #6
What mods have you put on it?

Winter also drops mpg hugely.... with the warming up of the vehicle... fast idle at startup... winter blend gas... it all adds up
These:

A set of 33 in mud terrain tires (I'll replace them for a 33-in Toyo Open Country AT III),
TRD performance air intake,
AFE throttle body spacer,
AFE 3 in exhaust system.

Also, it's not too cold here, around 40 F at the lowest.
 

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Not hard....highway driving. Cruise control at 69 acoording to waze. Truly made a big difference.

Do I like driving at 69......no, not really. But I like it more then watching my fuel needle fall like a lead weight.

Just nice ( for me ) to know that when i feel like it I can improve my mileage.
I must have posted right after you, that was meant for OP.

Still good info though!
 

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These:

A set of 33 in mud terrain tires (I'll replace them for a 33-in Toyo Open Country AT III),
TRD performance air intake,
AFE throttle body spacer,
AFE 3 in exhaust system.

Also, it's not too cold here, around 40 F at the lowest.
Yep, get rid of the heavy mud terrains and drive slower.

Most effective advice/mod you will get.
 

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Discussion Starter #10
Any advice regarding my plan to regear my FJ with a 3.91 or 4.56 gear set that I was told?

You can take a look at this chart and calculator, I got the infor from there.

 

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Buy yourself a scan gauge and setup to view instant fuel consumption then learn to keep that number as high as you can while driving. did that to the Wifes FJ she went from 12.7 to 17.9 MPG.
 
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Good idea. I will do that but the main point for me is how to save money on gas.
Buy a prius.

Not being a smartass.... it's just that an FJ is a solid body-on-frame suv. It's like a truck... but heavier and not as streamlined.
 

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Discussion Starter #19
Buy a prius.

Not being a smartass.... it's just that an FJ is a solid body-on-frame suv. It's like a truck... but heavier and not as streamlined.
I'm aware that I'm not going to get the factory 21 mpg on this 160k-miles truck but at least I want to be close to that number.

My wife has a 2015 Versa Note, funny car and it's great on fuel economy. Go to hell small cars-with-great-mileage. I'm jealous!
 
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