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Discussion Starter · #1 ·
I bought my new '08 IS350 last October and do almost entirely city driving. Here's the problem: I am routinely getting 10-12 miles per gallon (per the car's computer) and my own calculations!!!!

I have taken it for extended highway driving and managed to get 25-28 mpg. So I don't think there is anything 'wrong' with the car, but my city driving mileage number is just so low, I can't explain it. I live in SF, so I thought it might be all the hill climbing that could be dragging the average down, but still, 10-12 mpg???

My tires are inflated to the recommended psi, I don't drive like a maniac, and I use premium gas.

Any thoughts (besides doing more highway driving)?

Thanks
 

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honestly, not surprised for San Fran city driving.....

otherwise, make sure to always use 93 octane, dont put in anything less then that....I know its expensive out there, but still, use 93!
 

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Also... in addition to the hills... how are you driving the car? Are you "enjoying" all 300 hp? :p
 

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I bought my new '08 IS350 last October and do almost entirely city driving. Here's the problem: I am routinely getting 10-12 miles per gallon (per the car's computer) and my own calculations!!!!

Any thoughts (besides doing more highway driving)?

Thanks
This may sound silly but, every time you start, select snow mode, do it for a week or two so you can make accurate calculations, see if it makes a difference?!
 

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Are you doing a lot of idling around? Stop and go?
 

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Discussion Starter · #6 ·
What difference will snow mode make? I'll give it a shot anyway...

I don't do a lot of idling, just typical stop and go city driving. I do use the seat heaters a lot...is that the equivalent of using A/C?

Also, I don't even know if it's possible to get 93 octane in SF. I haven't seen it when I fill up. I'll keep looking.

What are other people getting for mpg for city driving?

This is a great car, but my city driving gas mileage puts me on par with the biggest gas guzzlers on the road!
 

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the car is still new. it still needs to break in. your mpg will go up later.
 

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I'm still new with mine as well (though I have a 250) and was also surprised at the MPG in the city. on the hwy it will get close to what it's supposed to, but in the city it doesn't get the 22 (I believe) that was on the sticker.

Here's a good rule of thumb, obviously you don't want to do quick starts but rather slowly accelerate and go through the gears as smooth as possible. But in addition and something people don't think about as much, but every time you tap the breaks, you're lowering your MPG. Obviously you have to stop at lights and turns, but the more foresight and coasting to near stops you can do will certainly help up your mpg. I do a mix of city / hwy and am averaging around 24mpg for the tank when i take it easy, at first it was around 21-22 though.

I'm hoping as others have mentioned that after the break in period it will go up a little
 

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Discussion Starter · #9 ·
Coasting to stop lights/signs is next to impossible here in SF, but not bad advice for when I'm on flat roads.

Has anyone ever heard of the IS350 getting 10-12 mpg in the city? Anyone out there? By the way, my car has about 1500 miles so far. Funny thing was, I traded in an IS300 for the 350 and I thought the mpg on the IS300 was low too.

At this point I am wondering if this issue is worth bringing the car into the dealer. I will probably get laughed out of there, but my mileage is so far below the EPA estimate that I feel something has to be wrong with the car. If someone else says that their new IS350 also got 10-12 mpg in city driving, I'd feel a little better.
 

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Not to make you feel bad, but I get an avg of 22 around town, and 27 hwy. I consider my 350 an economy car (with balls).
 

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I'm also in the bay area and in SF quite often and avg mixed highway/city driving is around 22 - 23mpg or so with a heavy foot. Even if you're only driving in the city it shouldn't go down to 10 - 12 mpg unless you're drag racing all the time. Maybe you've gotten a bad tank of gas and the computers all crazy due to that gas. I'd recommend first resetting your ecu by disconnecting your battery for a while then put on some more highway miles and use snow mode, with a new tank of gas maybe even try a different station you usually go to. With snow mode basically it makes the throttle pedal less sensitive. I always use snow mode when it rains in city and highway as well as when on the highway when I'm low on gas. BTW the highest octane you can get here is 91. 93 isn't available here in CA at standard gas stations. I'd recommend only sticking with 76, Chevron, or Shell.
 

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I've had my IS 250 A/T AWD for 10 days now. I am getting 19 mpg. I'm disappointed with that number and hoping it goes up. I do not accelerate hard, ride the brakes or warm the car up. I just drive like a normal person, and there's always someone driving faster than me.

I'm hoping mine goes up soon.

dobermandog, see what the techs think at your 30-day/1,000 mi free service.
 

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awd gets bad gas milage compared to rwd.. heavier and more drivetrain components to move around.
 

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Discussion Starter · #17 ·
If you complain about gas mileage then you should of gotten an IS250.

I get 23mpg via computer with 90% city driving.
EPA guideline for my car was 18 mpg city. I am getting more than a third LESS than that. Something's f'ed up, and it's not my driving. I am taking the car into the dealer in March for its first 6 month check up.

Thanks for the advice to those who posted - I put it in snow mode for a while and still get 11 mpg city.
 

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did you do the ecu reset and drive around conservatively for a while? That might take care of it.
 

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Check your air filter. I've found that on that car, an even slightly dirty air cleaner has a HUGE impact on gas mileage. Like 4mpg worth.
 

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I've had my IS for about 3 months now (8000km) and I just started realizing much better mileage. I used to get around 10L/100km (~25mpg) and now can get 6.7L/100km (~35mpg) highway driving.

I took this photo a couple weeks ago as it was hard to beleive the numbers. I drove 600km all highway a couple weeks before and got really good mileage, but nothing quite this good.

Looks like they just take a bit of time to break in.

 
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