11 mpg!?? (1 Viewer)

[RCsGX]

I bought my GX back in March '12. It was a 1 owner and the lady took very good care of it. Its always been serviced by the same local Lexus dealer and I have multiple pages of maintenance shes done through Lexus. Within the past 10K miles she had all of the fluids (except the trans) replaced and did the 90K scheduled maintenance with timing belt and water pump.

I bought it with a little over 100K miles on it. The problem is Im only getting 11 mpg!?? I started off replacing the air filter, cleaned the MAF senor and throttle body and did a Mobil 1 oil change. Last week I had both upstream air / fuel sensors replaced and I had Toyota do a fuel injection cleaning and 4wheel alignment. I had Toyota check to see if my brakes were dragging and they said they werent and Id know anyway since I had 2 bad calipers on my Tundra.

After all that Im still getting the same MPG? The only thing left is to replace the spark plugs but they should be good until 120K miles, plus with the exception of the shi**y MPG my engine runs normal. No pinging, no hesitation or rough / weird idling.

Anyone have any other suggestions???

 

[THEROK]

I think it's par for the course.

You are running taller/wider/heavier tires and the diameter will impact your speedo/odo so you'd want to correct for that so you're likely a few more miles positive on the readout.

11mpg doesn't seem too far off, honestly, or about ~210 miles before you have to refill. With that said, I do consistently get 13mpg with my even heavier MT tires. When I was running ATs like you, I was locked in around 14-5mpg.

I'm a single guy so don't haul people or stuff around too often. I do a lot of mixed driving. I removed my third row seats. I always run super unleaded. I ran about 37-40psi cold on the Toyo ATs and do the same with my MTs.

It's the one major downfall of the 2UZ-FE in this day and age. It's a guzzler.

 

[RCsGX]

I run top tier gas super gas (Chevron), always have. I removed my 3rd row seats, didnt help. Im usually driving by myself too, so weight isnt an issue. But besides that, I was getting the same exact mileage when I had the stock 17" setup. Mileage hasnt gone down since I put the 18s on, its stayed the same. Since putting the 18s on Ive tested my speedo against several speed traps and its spot on to what my GXs speedo says. I thought it might be a 1-2mph off but it wasnt?

I pulled my plugs a little bit ago and they look great and my engine definitely isnt running rich so I have no clue why Im only getting 11mpg? Not much else I can do......

 

[THEROK]

Something's up in the math/data fronts because mine definitely took a hit when I went from stock to 18x9 285 ATs by about 2-3mpg and then down another 1-2mpg with the MTs. Weird man!

 

[RCsGX]

It is weird. I fill up at the same Chervon station, use the same grade gas, same pump and I always fill up on Sunday. Ive always averaged 10.8-11mpg since I bought the GX back in March '12. The 18" setup is only 5lbs heavier per wheel & tire compared to the stock 17" setup so its not that much of a weight difference.

 

[THEROK]

How much do your tires weigh? They gotta be at least 50lbs? I'm curious to know how much the stock tires weigh.

 

[KS-Ryan]

What are your driving habits? Do you drive fast? Jackrabbit starts? Lots of city driving? What PSI are your tires at?

The GX was never a fuel miser but you should be able to do better than 11. Heck, I get better than that in my 3FE 80.

 

[RCsGX]

How much do your tires weigh? They gotta be at least 50lbs? I'm curious to know how much the stock tires weigh.

18" Nittos weight 47lbs. a piece. The stock tires weighed 38lbs. a piece.

What are your driving habits?
I drive like a granny! RPMs are around 2-3K unless I need to pass somebody really quick.

Do you drive fast?
No.

Jackrabbit starts?
No, smooth, RPMs around 2K-3K.

Lots of city driving?
ALL city, no highway driving at all.

What PSI are your tires at?
Fronts: 36 PSI
Rears: 38 PSI

The GX was never a fuel miser but you should be able to do better than 11. Heck, I get better than that in my 3FE 80.

Im not the one to bi*ch about fuel economy but something isnt right if Im only getting 11mpg.

I had a '06 Tundra DC (same V8 engine as the GX), weights almost the same, it had larger 33" M/T tires and I drove that thing like I stole it and I got better gas mileage!

 

[tick2791]

I know it doesn't help but i get 17-18mpg city/hwy mix and 20hwy. 130000 miles all maint. Done but do run regular allterrain tires not lt rated tire; i have heard lt rated tires have a higher rolling resistance but i do not know if it would make that much of a diff.

 

[GXO]

I just upped my MPG on the way back from GSMTR (15 before highway, 17 on the way home) by breaking and replacing my CV. Turns out it was bound up in the outer joint and probably impacted my fuel economy. I suspect your engine is running fine. There are other factors. Bearings, CVs, fluids, etc all can impact it.

I am lifted and running about 400 lbs over stock for the record with 285/75/17s. I measured my fuel economy with GPS.

 

[KS-Ryan]

All city no highway is your problem. You're never going to get good mileage around town. Short trips are worse as your engine doesn't get up to optimum operating temperature.

 

[RCsGX]

I just upped my MPG on the way back from GSMTR (15 before highway, 17 on the way home) by breaking and replacing my CV. Turns out it was bound up in the outer joint and probably impacted my fuel economy. I suspect your engine is running fine. There are other factors. Bearings, CVs, fluids, etc all can impact it.

I am lifted and running about 400 lbs over stock for the record with 285/75/17s. I measured my fuel economy with GPS.

Before I bought my GX I had a PPI done and nothing came back abnormal. The previous owner did have the left front axle replace at 75K miles.

All of the fluids have been replaced within the last 10K miles.

All city no highway is your problem. You're never going to get good mileage around town. Short trips are worse as your engine doesn't get up to optimum operating temperature.

I got fine gas mileage in my Tundra? I took the exact same route I did when I had my Tundra yet I got better mileage in that? Maybe I should lift the GX and throw 33" M/T tires on it.



Im moving to Florida next Tuesday. Id like to see how the highway mileage is but Im going to be towing a 6' x 12' U-Haul trailer so thats no good. I'll probably be filling up every 200 miles if not sooner. Wish I had my Tundra!

weeeeeeeeeeeeee

 

[KS-Ryan]

GX is AWD while your Tundra was part time.

 

[RCsGX]

Yes BUT my Tundra had heavy azz 33" M/T tires (I was a little over 20lbs. of unsprung weight per wheel / tire) and a larger fuel tank yet I was getting 3-4mpg better and I drove that thing like I stole it!

Besides that, most guys here are getting at least 14mpg city driving in their GX and 16-20mpg city / highway. Im hoping the ECU needs a few tanks of gas to fix the settings since I changed the air / fuel or the injector cleaner will help in the next few tanks. We'll see what happens.......

 

[Corbet]

I agree something is off. My built 80 series pulling a trailer in the mountains gets 11.

But I don't know where to point you.

 

[THEROK]

just to serve as a ref point with my heavy 10-ply MT tires (at least 16lbs per tire heavier than rc's ATs), my latest fill-up:

250miles
20 gallons
12.5mpg or a little higher given the diameter of my tires are about 2" taller than a stock tire. so let's call it 13mpg corrected.

 

[bamachem]

I'd be willing to bet that you have a front O2 sensor that is on it's way out. Get a pair DENSO factory-spec replacements via amazon for a few hundred bucks. For some reason, the Toyota O2 sensors only last about 110k to 130k miles. It's time.

 

[RCsGX]

I'd be willing to bet that you have a front O2 sensor that is on it's way out. Get a pair DENSO factory-spec replacements via amazon for a few hundred bucks. For some reason, the Toyota O2 sensors only last about 110k to 130k miles. It's time.

Ive already replaced both upstream O2 sensors when I started this thread back in May....

The problem is Im only getting 11 mpg!?? I started off replacing the air filter, cleaned the MAF senor and throttle body and did a Mobil 1 oil change. Last week I had both upstream air / fuel sensors replaced and I had Toyota do a fuel injection cleaning and 4wheel alignment.

Im getting 240-250 miles per tank which is pretty sh*ty but Ive done everything I can (other than replacing the spark plugs) so it is what it is.

 

[bamachem]

Strange.

I have a 2008 4Runner V8 4WD - so it's the same drivetrain as your GX.

In 80/20 mixed Secondary/City driving, I consistently get over 19 MPG. Interstate is 20 MPG @ 70 MPH. That's with a 2" front leveling lift, tricked rear airbags for 1/2" rear lift, 1.25" wheel spacers, and OEM size Bridgestone Dueler HP tires (265/60/18).

I'm about to swap all lubricants over to Amsoil. When I did that to my 07 Land Cruiser (also same drivetrain), I got an 8-10% increase across the board in MPGs.

At 11 MPG, I would suspect that you either have a VERY heavy foot, drive in nothing but stop/go traffic with lots of idling, or there's something wrong.

 

[GXO]

I increased my fuel economy by double digit % by fixing warped rotors and other worn parts, another fun time.