jzdulexus

I notice that from 2010 to 2011 there was a big jump in economy from 18/25mpg to 20/27mpg in IS350. I know its not a lot, but still pretty significant. Anyone here knows what exactly changed?

604GSE21

maybe toyota change the way they measure fuel economy or ecu update? i don't know could be anything...

Bichon

Only change I'm aware of is the oil; both recommended and factory fill changed from 5W-30 dino to 0W-20 synthetic.

The protocol for measuring fuel economy is comprehensively defined by the EPA. Ask Volkswagen what happens if you get caught playing games with EPA testing.

jzdulexus

I didn't realize engine oil would make such a yuuuge difference.

355F1

Isn't that the year the EPA changed the testing procedure for MPG???

Bichon

No, that was a few years earlier - the change in testing happened for the 2008 model year.

Jeff Lange

iTrader: (1)

IS250 switched to 0W20 for 2011, IS350 didn't change until 2014.

Jeff

Rezno

iTrader: (1)

No idea. Honestly I feel like fuel economy ratings are nonsense. That being said, don't expect to get 50+ MPG on a 3.5 V6, but the city and highway ratings really just matter on how you drive. I averaged 22.3 in the city on my 2007. If you want to get 20 MPG city you can do it regardless of the year. Unless there is some ECU tune they did between those two years, I don't really see any logical reason for that. Unless they noticed its possible to get higher MPG and advertised it with the higher rating, then maybe.