I6turbo

iTrader: (1)

How accurate is your on-board fuel mileage computer? Mine seems to indicate about 2 MPG better than I'm actually averaging. The "instant MPG" readout seems to be about 3 MPG optimistic on the highway.

Further on the subject of fuel mileage, the LS430 seems to go waaay further on a tank of gas than the GX (both tanks are ~ 23 gallons capacity). Now that I've calculated the GX mileage, I'm wondering if the LS isn't getting even better mileage than the fuel computer indicates. Computer says I'm averaging ~21-22 mpg all around on the LS, but to watch the gauges you'd think it was burning about half as much as the GX making the same trips.

The G Man

My MPG computer is also 1 to 2 mpg more than actual, I think every GX owner have about the same difference between actual vs computer. BTW the LS is rated higher by the EPA for gas mileage.

BobsGX

I have yet to see any on board mpg meter that was correct. No matter what brand of vehicle they were in. They are always optimistic by 10-20%. But of course, YMMV.

sayadil

EVEN though same tank capacity and V8.. don't forget LS is much lighter then GX.. which contributes to lot of fuel efficiency by the LS.

BobsGX

The GX V8 is also a larger engine 4.7 L vs the 4.3 L V8 in the LS. Also the GX has the aerodynamics of a brick compared to the LS. That there makes a big difference in wind resistance thus the less fuel economy in the GX.

trebien

Lighter wheels and tires, ligher vehicle... etc. There's many obvious reasons why the LS gets better economy.

Granted, the instantaneous mpg reading is fairly useless, but I reset the trip mpg meter at every fill-up, then compare it at the next fill-up, using the miles travelled by the trip odometer, and the total gallons to fill the tank back up. It seems to be spot-on... within .1 mpg or so.

CVsIS250

Ah yes...the infamous lying computer. Mine is 1-2 mpg above what I am actually getting.

CV

I6turbo

iTrader: (1)

I understand the differences in mileage ratings, Cd, weight, etc., and why the GX will get lower fuel mileage. My point was that the LS seems to go about 2X as long on a tank full, instead of the 27-39% better mileage that the ratings indicate. I guess the thing is that the LS gets better mileage than the EPA ratings claim (they do), while the GX gets about what is claimed. That, and the LS isn't REALLY going that much longer -- it just seems like it. This is a good case where working the actual numbers exposes the rough estimations and the "it seems like" impressions to be false. My GX got 16.6 on a tank of mixed driving, so that's acutally not bad for the weight and type of driving. The only time I've actually calculated the LS mileage was on 100% interstate driving, and it was 26.7 mpg. Apples to oranges, since the GX tank was burned mostly in city driving. The LS SEEMS to get great mileage in mixed/city driving too, but I haven't checked it other than via the computer.

sayadil

well how much milage r u getting out of ur GX... my 04GX gives about 375 (most average) on a full tank.. and one person i know who drives 2005 LS only gets 490 thats not twice as much... i'm talking about everyday driving in city of Toronto. i doubt it will double even on a hwy run... I just follow odometer/gas for real estimate of fuel milage rather then the Unreliable On board Computer.

Threxx

Every single Toyota and Lexus on board MPG calculator I've seen to date has been OVER optimistic by at least 1, up to 3 MPG. This is regardless of milage (time to 'learn'), driving habits (heavy foot, light foot, medium foot) or anything else.

It's annoying to me that they've obviously set these things to guess on the high side of the spectrum I suppose maybe hoping people will take the readout at face value and not bother to do the math for themselves.

I6turbo

iTrader: (1)

I guess 16.6 isn't too bad for mostly city driving in a largish vehicle like the GX, but compared to the LS it is noticeably worse. However, it's way better than the worst I've had -- a 460 c.i. F-250 HD 4X4 back in the late 80s. That thing actually got 4-6 MPG despite having a much higher EPA rating. I started getting suspicious when I found that I couldn't fill the tank with the engine running.

BobsGX

[QUOTE=

It's annoying to me that they've obviously set these things to guess on the high side of the spectrum I suppose maybe hoping people will take the readout at face value and not bother to do the math for themselves.[/QUOTE]

Thats exactly what the manufacturers are counting on.

CVsIS250

They also want you to think you are getting better milage than you actually are so you don't panic as gas prices increase.

CV

V8_Fan

I get the same result in my LX...computer indicates 2mpg better than reality.

CVsIS250

Yeah, I think that it is a worldwide Toyota/Lexus thing.

CV