Ok, there have been a few threads on ETC Power mode vs Normal and it got me curious. When I first bought my 08 IS350 I was scared that it would destroy my mileage so never used it. Especially since HEAVY city traffic jam mileage occasionally dropped me to the 18mpg range.

But I got curious and spent the last month driving the same route to/from work. It is about 90% city vs 10% hwy.
My eval of ETC vs Normal mode is that it really depends on traffic.
Driving style (aggressive vs gas conscious) made little difference.
On some days ETC mode got slightly better mileage while on others Normal.
As expected stop and go traffic killed mileage regardless.

For overall mixed driving (50% freeway) both my wife and I got better overall mileage leaving ETC mode on all the time! (we got about 18.x mpg using Normal vs 21.x mpg ETC). Not a huge difference but considering the snappier performance a win-win for us. We both are a little heavy on the accelerator (hey, it has 306hp!)

Freeway, of course, doesn't matter unless you are in traffic and the car shifts alot. On 2 recent trips from Seattle to Portland the computer said average speed trip average was 29.8 (darn Portland dropped it from being over 30 each time).

Anyway, I thought I would share. For my wife and I we leave it in ETC mode all the time now.

regards

I hate using the ETC mode on my IS350. When I had my IS250 I used it all the time as I needed to somehow make the car feel fast, it's just too damn slow hence why I sold it. Now when I turn on the ECT mode on my 350 I just hate it, especially when I let off the gas. It just hangs in the gear way too long waiting for me to step on it again. I think the Lexus engineers could have done a better job with this. If i'm flooring it and let off the gas, don't let it hang in the gear for more than 3 seconds. It stays in that low gear forever at high rpms before it decides to upshift. If I want to go fast now I just use the paddle shifters, that way it will upshift when I tell it to.

What i'm trying to decide is what the ECT mode really does, I have feeling it does more than change the shift points. If i'm driving in normal mode and flip it to snow mode i'll feel the car slow itself, as it adds more resistance hence helping the losing grip in slippery situations. If I flip it from normal to ECT power I feel it give less resistance than the normal mode while maintaining a constant speed and RPM. Does anyone else notice this? It makes the tranny feel more free.......

It probably modulates how sensitive the accelerator is to pressure.

From what I understood using the ECT Power mode keeps the transmission in the lower gears for a longer period of time for better performance, sudden braking & acceleration. I personally love it, & I only have a 250. Only problem is my wife then telling me to 'slow down!' when it's active

I have noticed that if you come to stop quickly it holds the rpm's or sometimes even raises it for a few seconds. Is that what you are experiencing? I just figured it was either to keep the torque potentially up or the port injectors were kicking in. Otherwise it doesn't seem to hold the rpm's -- especially for 3 seconds..

One thing that helped us was taking it back to the dealer and having they reset the learning mode. Much better response.

As a note I noticed that my wife averaged 22.x mpg yesterday. Before ETC she would have been in the 19.x range for sure.