My average so far is 22.8. I'm on freeways 80% of the week going about 70-85mph. If I slow down a bit and not drive aggressively, I get about 24-25mpg.

 

07IS350. Bought used at 7K Miles.

Now at 12K miles and average of 24.2 MPG for the 5K miles I've owned it for. 80% city / 20% HWY.

 

i get an average of 19.2MPG. 60% city and 40% highway.

 

2006 IS350 I Currently average 22.5 MPG Mixed, 28 MPG Freeway. But i WILL BE AVERAGING 33.25 MPG Mixed and 40+ MPG City after my Hydrogen Fuel Cell Prototype modification $$$$. Look out for my upcoming thread in about 2-3 Weeks after test phases are complete.

My website will host all data, photos, and test reviews.

-Cthru

 

07IS350 w/18k miles avg 24 with 50% city/hwy. Best tank avg 29.5

 

Since this is bumped today, I just set a new personal best on the range computer..

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Tank AVG was 33.8, calculator says 31.6, 85% hwy.

 

On my 2008 IS 250 last week on a trip to the UP of Michigan. 28.3 on the way up. 30.5 on the way down. Both times averaging around 75 mph. I don't understand the sudden increase. I am overall real happy with the gas mileage.

 

Best of luck with that, but I'm reserving the right to laugh when it makes no measurable difference at all except to your wallet.

 

19mpg with 75% city and 25% highway.

 

22.0mpg about 70% highway 30% city. Also, it's pretty hilly around where I live so that makes a bit of difference.

 

IS250 - with normal driving and mixed city/hwy, i get between 27-29mpg usually.

 

Recently drove a loaner 250 AWD w/ 40K miles and, to my surprise, the lifetime MPG was at 21.8.

The lifetime MPG on my 350 is at 21.7.

 

Just rolled over 20k on the 350, lifetime average 24.7, last few tanks have been between 26.8 and 27.2. 90% freeway cruise control set to 70

 

We installed on 4 test vehicles one of them being a IS250. IS250 reported a result of 47 MPG HWY. We will be isntalling the prototype in my 350 in less than 2 weeks. All information will be documented and posted in separate thread also on my website.

Corolla: over 70 MPG
Civic: Over 62. MPG
Hummer H2: 17 - 18.xx MPG

The IS250 was a bit more complicated in the installation due to the advanced O2 sensors and onboard computer.

All vehicles were tested with 1 tank of gas on a 2-3 day span due to prototype. The prototype passed final inspection for errors and will be awaiting a final install on my vehicle which it will reside permanently. From there there will be several tests that will be ran including

SF Bay to Los Angeles
SF Bay to Las Vegas
City driving.

All MPG will be recorded from Lexus onboard computer and Scangauge II.

Maybe the results will make you want to get one installed

 

Several factors conspire to make the number low:

The "lifetime" mpg can be reset. Easily. I reset it after I drove off the free gas from the stealership.

People beat the living tar out of loaners. That's what i do =)