bwallace2

Before it started getting cold in my area i had 4 new Michelin tires put on at the local tire shop. The tires i added are Michelin Cross Terrain SUV (Highway All-Season) OE tires. I asked for a alignment, but not so sure i got one. Anyways i later had it aligned at lexus and in for some work do to a large drop in mileage following the addition of the new tires and a few other things. The 03 GX 470 currently has about 106K miles on it. I think the average mileage is now around 11.5 miles per gallon (honestly mostly highway) from our usually getting 16-17 or better on same route. As the same issue continued following the alignment with the mileage problems, per my request I had the tires balanced and rotated on another trip the dealer mentioning my issue with mileage again. The air filter is new and clean. We are being told the mileage loss is due to the winter and winter gas.... I have read posts and asked around a few times for ideas to fix this issue. The temperature gauge is running fine and the tires are the right size. I'm not sure what the issue is and we can't seem to get help, but something is not right.

I have dodge ram 05 1500 (70K miles on it) with a hemi. with a 24 to 25 gallon tank and its getting better mileage when calculated out compared to the lexus 470 per tank. The lexus i believe is 19 gallon tank. I had my wife gas up at the same places I gassed the truck up at so we could compare the bad winter gas myth. My truck is getting up in the 300-330 a tank range. the lexus is averaging 260s to maybe 300 once out of every 5 tanks if we are lucky. 300 is really nowhere to be seen since we had the tires put on. The regular is in the 270s. The change to warmer weather is not really producing better mileage either.

Anyone have any thoughts on this or things i could have checked. We are thinking if we can't get it figured out a new car may be needed.

BlairC

if no other factors changed, i think you got a bad alignment. i would take it to a trusted shop and have it redone.

bwallace2

Well, the alignment was done at the lexus dealership. When i got it out of the local tire shop and it was rough and seemed out of alignment i went straight to the dealership. All the work done on the car minus the initial mount and balance of the tires has and will be done at the dealership. I was hoping the dealer could have dug up something on the fuel issue, but it still seems to be an issue.

sphy1005

iTrader: (3)

Even with a bad alignment would it really drop the mileage that much. Seems excessive to me. I know you said they are the same size tires but are you sure..You could also post in the LX forum too...This is GX..

bwallace2

Sorry about that my wonderful typing skills got me again. This topic is about a GX not LX.

snhrph

The gas tank in your GX is 23 gallons.

I find it highly unlikely that lack (or badly performed) wheel alignment will cause that much of mpg reduction and not manifest istelf in any other manner... You would feel it at the steering wheel, you would hear the tire noise, handling would be way off, etc...

With that in mind, (I'm sure you've checked), but I'll ask just in case - have your brakes been inspected? Toyota 120 platform is notorious for sticking calipers.

Have you noticed any other changes - vibrations, noise, odor, etc...

I have replaced tires recently on both trucks and did not bother with wheel alignment. No significant change to GX mpg since I went with stock size. I lost almost 2 mpg on 4Runner because I went up a size to 255/75/17, that was expected.

Also, you should not calculate your mileage over 1 tank of gas. The more miles you factor into your calculations, the more accurate your result will be. There are plenty of discussions on this board on how to calculate your true mpgs. There are numerous apps for smart phones that do the math for you.

ROSCOGX470

Using your figures it seems there is an average of 270 miles per 19 gallon tank which would put you within normal range of 14.2 miles per gallon. Mine gets 14.5 mpg's with 50/50 highway and city and I have an 04 with 78k. Not sure you can expect much more with over 100k.

wokraku

Do not agree entirely. Judt did about 313 miles on my '03 Lexus w an avg of 16mpg. My GX has 108k on it....

RioDino

Sounds more like a fuel line issue, but that should not have come up suddenly. Try some heavy duty Gummout for a tank or two. See if that gets the injectors clean.

When did you last replace the spark plugs? If you changed them recently, did you use OE platinum plugs?

I run K&N filters in all my Lexus vehicles. My 2004 GX 470 has 80,000 on it. I average 18.5 mpg and get up to 22 MPG on the highway. I got 15% better mileage when I moved to a K&N filter.

Yes, winter weather drags it down.

Good luck. Let us know what you find out.