Excellent mileage on IS 250
04-15-10, 02:11 PM
#1
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Excellent mileage on IS 250
Just want to post something positive about my 2009 IS 250 RWD auto. Since I got it brand new, I have done 8,800 miles and have calculated my mileage over 22 tanks of gas. Altogether I'm averaging 29 mpg!
Each tank I put in around 14.5 gallons of the cheapest 93 I can find (usually Hess) and do around 425 miles. The MID always reads about 2 mpg higher than what I calculate. Range shows high 400s after fill up and I have driven past 0 many times. The fuel light comes on when you have 4 gallons left in the 17.1 gallon tank.
Surprisingly, the car is driven 80% on city streets! However, I don't drive in heavy traffic so I use some hypermiling techniques like timing traffic lights to not have to stop and coasting in-gear to make the fuel cut off.
With my light foot, the auto upshifts to 2nd, 3rd and 4th at 2,000 rpm, but then there's a deadspot in acceleration when it upshifts even earlier to 5th and 6th and there's no torque down at 1,200 rpm. Luckily on my 20 mile commute I can cruise most of it at 50 mph with the instant mpg showing 45 mpg. Mileage starts to decrease over 55 mph so when I drive on the highway at 70 mph, I get around 30.5 mpg.
A/C is always on except in winter but my mileage didn't change probably because the longer warm up times and engine running rich negated the savings from not using the A/C. I remember when temps were 40F, I drove 7 miles before the torque converter would lock up and the tranny would shift to 6th. So if you make short trips in the cold the engine may never reach operating temp and your mileage will be trashed.
Mileage was a big factor when I chose this car over the IS 350, G37 and C300. I also looked at the TSX, A4 and 328i.
So, is there anyone else here interested in good mileage? I'm looking out for the BMW 335d and Infiniti G25 which should be very similar to the IS 250.
Each tank I put in around 14.5 gallons of the cheapest 93 I can find (usually Hess) and do around 425 miles. The MID always reads about 2 mpg higher than what I calculate. Range shows high 400s after fill up and I have driven past 0 many times. The fuel light comes on when you have 4 gallons left in the 17.1 gallon tank.
Surprisingly, the car is driven 80% on city streets! However, I don't drive in heavy traffic so I use some hypermiling techniques like timing traffic lights to not have to stop and coasting in-gear to make the fuel cut off.
With my light foot, the auto upshifts to 2nd, 3rd and 4th at 2,000 rpm, but then there's a deadspot in acceleration when it upshifts even earlier to 5th and 6th and there's no torque down at 1,200 rpm. Luckily on my 20 mile commute I can cruise most of it at 50 mph with the instant mpg showing 45 mpg. Mileage starts to decrease over 55 mph so when I drive on the highway at 70 mph, I get around 30.5 mpg.
A/C is always on except in winter but my mileage didn't change probably because the longer warm up times and engine running rich negated the savings from not using the A/C. I remember when temps were 40F, I drove 7 miles before the torque converter would lock up and the tranny would shift to 6th. So if you make short trips in the cold the engine may never reach operating temp and your mileage will be trashed.
Mileage was a big factor when I chose this car over the IS 350, G37 and C300. I also looked at the TSX, A4 and 328i.
So, is there anyone else here interested in good mileage? I'm looking out for the BMW 335d and Infiniti G25 which should be very similar to the IS 250.
04-15-10, 03:28 PM
#5
I get 17-20 with a heavy foot on the IS350.
On 300 mile intercity drives with virtually 100% highway miles, I get a pretty consistent 24.5 - 26.5 MPG with a heavy foot (plenty of hard accelerations here and there). I average around 90 MPH during these trips, if it matters.
Could probably get 27-30 if I tried to be fuel efficient, but only for 100% highway driving
On 300 mile intercity drives with virtually 100% highway miles, I get a pretty consistent 24.5 - 26.5 MPG with a heavy foot (plenty of hard accelerations here and there). I average around 90 MPH during these trips, if it matters.
Could probably get 27-30 if I tried to be fuel efficient, but only for 100% highway driving
04-15-10, 04:18 PM
#6
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I had a thirsty Nissan V6 before, so the 250's mileage has been nice. I get about 28 mpg with a 70% highway/30% city mix in my 250RWD, and my wife gets about 26 mpg with a 50/50 mix in her 250AWD. Wouldn't mind the extra oomph of the 350 next time, considering you get 50% more hp with only 15-20% less mpg. 
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04-15-10, 06:19 PM
#9
Lexus Test Driver
My IS350 get 28+ mpg on the highway at 70 mph and the best so far is 30.6 mpg.
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