Robclzr

Hi Guys I need help with my 2005 GX I just get 200 miles on a full tank on the city and 270 on the highway and is killing me, I tried replacing spark plugs, air filter and oil change and nothing has improved since then the average kn the computer shows 12.3 but is not even close.
please any help is appreciated!
thanks.
rob.

shyguyF

Clean mass air flow sensor.
Check your tires pressure. If you tires is too old you should put a new set on. I have just put a new set of Michelin defender LTX 275/60/18 tires on my truck. It grips and so quiet and gas mileage also improved.
Especially go buy this BG44K fuel system cleaner. It works magically. Check it on Ebay, the more you buy the cheaper you get.
My trucks is 06 and 110k miles but gas mileage is still very good. The computer shows 17.8 and I always get 17.5 in combination between city and high way.
Hope this helps!

chiph9

You can click on the image in my signature to see my gas mileage. Mine is so poor because I spend a lot of time idling in traffic (thanks, City of Austin for not building the roads we need!)
Fuelly will also show other drivers of GX470s for your year so you can compare.
One thing you shouldn't do is trust the in-dash MPG display - it's always wrong. Calculate it the old-fashioned way by dividing gallons into miles travelled, the next time you fill up.

Chip H.

Matsui

Based on a response from a member here in a recent thread, changing the MAF and oxygen sensors helped him get rid of this problem. I have a similar issue where all of a sudden my car's MPG dropped from 17 to 14 and from 330 to 260 miles range between fill ups. I've already done spark plugs, TB cleaning, air filter, gas cap, tire pressure but nothing has helped. I'm planning to replace MAF and oxygen sensors when I do my next oil change and see if it makes a difference

NMBruce

I live in a small town in the mountains and around town, my avg is 12-13, lucky if I can get 14. Highway driving ranges from 14-22, depending on my speed, head winds or not and pulling a small trailer. Under 65 mph, 18-20 is normal, 75-80, 15-16, strong headwind anything over 65 or so, forget it, where's the next gas station. Still it's as good or a little better than my 2013 Jeep Wrangler unlimited Rubicon.

IanB2

Ours doesn't get great fuel economy either, the biggest drawback of this vehicle for sure. I did all the baseline maintenance items when we got it, and nothing seemed to help. Next set of tires will be stock size to see if that helps at all. I've been applying a correction factor of 1.06 to the mileage when I enter the fuel up into fuelly.com to account for the larger rubber.

Organized Garage Status

260 miles per gallon sounds like what I've been getting since I got mine at 64k miles, which is reasonable. I have never really expected any V8 to give me any better than 14mpg. Even my good old SC400 never got passed that mixed of freeway and city.

Booyah

In the summer I can get around 300 per tank, and that is no highway driving--winter time Im down to about 220

LoneHiker

As NMBruce was alluding to, there are two things that kill mileage on the GX: speed and city traffic. If you can spend most of your time driving steadily in the 45-65 mph range, you'll get mileage around 20 mpg. Outside of that range, mileage will drop like a rock. Premium unleaded gives a slight mpg boost, but not nearly enough to offset the higher cost of premium.

Larger tires also cause a major reduction in mileage, and require that you apply a correction factor to calculations.

So before throwing a bunch of parts at the problem, just make sure your driving circumstances aren't what's killing your mileage.