On the way home from Vermont, I decided to go easy. I set the cruise control at 65-68mph. Traffic always runs faster than that so I was able to keep it set for longer periods of time. I achieved a whopping 23.5MPG over 190 miles of highway driving. Not bad! Around town, we get about 15-16mpg.

 

The best I got so far is 19 MPG cruising at 75 MPH.
BTW, what is your tire pressure? I set my tire pressure at 35 psi, the recommended 32 psi is too soft.

 

That extra 5+MPH makes a big difference. Not only because the engine runs at a higher RPM, but also because it is more difficult to maintain that speed (normally) without having to alter cruise control more frequently. I was able to maintain cruise 90% of the trip.

I think the tires are set for 32psi but then again I had the vehicle serviced not too long ago and the dealer loves to tinker with the tire pressure.

 

That's really impressive. I assume your mileage is hand calculated and not off the trip computer. The best I have been able to get, which was roughly a 50/50 combo of in town and freeway driving, is 17.1 MPG hand calculated. It wasn't a deliberate attempt to maximize mileage under those conditions. I did get 29.5 MPG on the ES330 during a 200+ mile round trip, about 95% freeway.

 

No it was based on the trip computer and this is because we haven't filled up yet and have been driving around town now. Do you believe the trip computer is off?

 

The computer reading on my 03'GX is off by at least 10% on the higher side. In my daily driving, the trip shows ~20mpg whereas in reality I am getting ~17.5mph consistently. Also, I think the computer is way off after a recent reset. Once reset, it gets closer to truth after a few fillups.

Still computer reading of 23.5mpg is very good

 

The trip computer reads about 2 MPG high from hand calculation. I even had my computer replaced, which had a supposed fix, but it didn't make any difference. Even with that, 21.5 MPG is still great mileage and shows what can be done with sensible driving. I do reset the MPG at each fillup.

 

I bet that speed is at the lower end of the gear meaning less RPMs and the engine works less. Going down to FLA, I averaged 19=20 MPG 65-75 MPH.

It is pretty good considdering what a massive engine it is. Ooooh, I love the sound it makes from a stop when I step on it. It is inspiring!

Hehe, I feel so american: "I NEED OIL FOR MY HUGE SUV".
"OIL! *slurp* *slurp*"

LOL

Love the GX!!!

 

So far the trip computer in my 05’ has proven to be within two tenths of a mile per gallon. I get 16.8 city and 20.5 to 22.3 highway. I think the variable valve timing in the new engine must help. Only have 2600 miles on it so far, maybe it will even get a little better after 10,000 or so.

 

Absolutely! The lower you can maintain RPM's the better the fuel efficiency. At 65mph, RPM's are pretty low. The number isn't coming to me.

 

The VVTI engine must make a difference, I agree. I have the 04 so don't have the pleasure of testing that.

 

I get about that same accuracy. I did the calculating with fillup totals and mileage over about 5 fillups. I noticed that the average on the computer was +.3 (or 1.8%) on the computer. I think that is close enough for me to call accurate and not stuff my storage bins full of gasoline reciepts.
With that said, my over all average is about 16.7mpg for mixed driving. On trips, depending on the road grade, pitch and wind direction, I have seen it go between 19 and 22 on the highway. I too, noticed that just above 75, the mileage (mpg) starts to fall off pretty dramatically. For the size of the vehicle, I think we're doing OK.

 

so far, the best i've gotten was about 21mpg (hand calculated). i never trust the trip computer. and i achieved 21 mpg by, like what looknow said, cruising around 65-70mph