Fizzboy7

I recently took a SoCal trip on a mostly flat, two-land road, for about 130 miles. On a very slight downhill, I averaged 38 mpg's at 61 mph going. Coming back, with a slight uphill on the same highway, I averaged 33 mpg at 62 mph. There were only two stop lights on this entire stretch. This nearly matches my 2020 IS350.

I'm very impressed with the numbers. I had a few people follow me, but mostly kept up with traffic and didn't stand out. The 3.5 V6 is a great compromise of power and efficiency. I feel this is approaching hybrid numbers without paying for a hybrid.

cerbois

Nice. I thought it was just me. with only a few hundred miles on the IS350 and while switching thru the dash computer I was seeing what I thought was ridiculous MPG numbers on the highway. I guess not after reading your experience.

BBQapple

Reset the MPG, drive normally for a week, then come back and tell us what you see.

I don’t know about you but my life has me driving in actual cities, in traffic, waiting at red lights. Just because I can get 30mpg on a summer trip across the state doesn’t change the fact that our car has gotten 19mpg average since we bought it.

The engine is a pretty BAD balance of power and economy, and the power isn’t even that useable with the high rpm torque peak.

That said I love this car (23 IS350).

arentz07

Yeah I managed 21-22 MPG overall in my 2021 IS 350, with it able to achieve about 30-31 on highway trips at 75 MPH or so. It's not... bad, but our 330i made it look really inefficient with an overall average of just about 32.0 MPG over the time we had it.

BBQapple

I’d love to see a V6 hybrid on the next IS but seems unlikely. 400hp and 30mpg should be doable.

cerbois

two weeks and two re sets netted 28MPG per week for me. Only a hand full of pulls to 5K as I m breaking her in.

Fizzboy7

That is quite good for the V6 with 311 hp. I would be satisfied with that.

Fizzboy7

The good news is I did reset the trip computer at the beginning of this trip. I also did the same trip when the car was new in April and got the same numbers. I think it's pretty safe to say this is how it will be. I must admit though, I go out of my way to be easy on the throttle. And mostly level highway at 60 mph is likely going to yield some of the best numbers for any car.
Anyway, I am happy to pass the info along and hear about other people's responses. The idea here is to show if one goes out of their way to achieve optimum numbers, it is possible with the IS350.

BBQapple

Well I suppose I could quit my job in the city which would keep me out of rush hour traffic, will have to stop taking my kid to school in the city also though. I could probably go grocery shopping at night and get straight on the highway to shop at a far away store each time.

But driving the IS350 in Dallas traffic nets me or the wife around 19mpg on top tier 93 octane gas. And it’s been months since I’ve floored the accelerator and she drives like an old lady.

DarrylT

What is the engine rpm at 75 mph? I just drove back from Asheville, NC to Cinti Ohio in the wife's 2005 ES. It has a 5-speed (auto). I experimented through observation, along the way, and found the mpg increased when the car was doing 72mph, and showing a corresponding 2300 engine rpm; this with cruise control on.The best I saw was 27.5 mpg where it held steady until I hit local rush-hour traffic. Any similar observations with the new IS 350 F-Sport (RWD) 8-speed?
TIA,
Darryl
PS I ask because I am expecting delivery on one. BTW!! Btw, where I live potholes are a year-round bumper crop. the 18s on my '13 Golf-R have survived all this time, until last year when a rim was bent. Cost me $120.00 to repair. Not bad for around here. My IS comes with 19s. I understand the tire pressure is supposed to be 36 psi on all corners. My R runs 41 psi all around. Does having the adaptive suspension help save those 19s?

arentz07

I don't recall the exact RPM these cars will do at 75, but I think it's barely over 2000, if I recall correctly.

MPG will always decrease when you get to higher speeds regardless of RPM because of wind resistance. Wind resistance increases as you go faster (specifically, by the square of the speed you're at).

cerbois

if driving in the city mostly then an EV might be best(or a turbo 4). As stated I doubt at 70MPH in 8th gear it s even 2K RPMs.
can t blame the car under certain conditions if it fails to meet the EPA numbers.
You ll be fine on the 19s. The car has a pretty soft suspension. Adaptive suspension will only turn it to a harder suspension when set.

Undefeatable

I live in Southern California, my driving is mixed suburban streets and freeway, but mostly street. My average on my 23' IS 350 is 23mpg.

Funny enough, my last car was a 2009 Scion xB, which had a grand total of 130 hp and I averaged maybe 24-25 mpg, so I am fine with the IS one given my mostly street driving.

ScytheDC

Do you only drive on long straight roads with no traffic? If so, then yes your mpg will be about the same all the time. But most of us don’t drive country roads all day. Therefore, the mpg figures are more realistically going to be lower on average for the population of owners. What you’re showing is an extreme example - mpg figure on ideal road conditions that most don’t experience.

laobo979

iTrader: (5)

Average mpg don’t mean much. Look at your full tank range and divide by tank gallon for true mpg. I dout it say you got 500 miles on one tank.