JTK

Currently using my wifes IS250 for a few days. Took in for a service and got a IS350 loaner. As expected, the 350 makes quite a bit more power - however, the 350 engine does not feel as refined and quiet as the 250.

My previous encounters with the 350 were very limited (short test drives), but this time, on my usual daily route with moderate traffic, I got to spend a bit more time with it and just surprised how much "rougher" the 350 is.

Given the choice again, I would purchase a 350 over a 250 - however, just very surprised at the lack of engine refinement. Maybe I just got a rough/abused loaner...

vapid2323

Not sure a loaner can be abused more than my two 350s; But with that said, they are different engines with different injection systems. And the 350 engine has been rated in the top ten from '06 to '09 I believe.

So not sure what you meant by refinement but I would say that the 350 has plenty

nosurprise

iTrader: (1)

Well, I test drove both 250 and 350 a couple years ago. With the 350, you definitely feel more when you accelerate and when it shifts. The 250 feels smoother when you accelerates; otherwise it feels about the same to me.

Make sure you tried out the power mode in the 350, it feels very different -- not sure how it compares to the 250 power mode.

edgeucated

iTrader: (4)

The car could be jerky because it learns the driving habits of previous drivers, and given that it is a loaner, i bet a lot of previous users just stomped on the gas pedal.

If you really want to be sure, you have to reset it and let the car relearn your driving habits. The 350 should be just as smooth as the 250

iRock

iTrader: (12)

I'm surprised someone has a 350 loaner. I wouldn't call it less refined. You got more power so you feel it.

#IS350

how do you reset it?

4TehNguyen

iTrader: (1)

disconnect the negative terminal of the battery for a few minutes. As a heads up it will lose your memory seat settings so have the seats in your setting before you pull the battery cable. Then when you reconnect it its already in the spot you want it to redo the settings. You'll also have to do the roll down window reset.

Gville350

iTrader: (10)

I totally agree with this statement!

mong

iTrader: (4)

They gave me a 2013 is250 as a loaner. The 250's engine is alot quieter than the 350's engine but I think is due to the 350's direct and port fuel injectors.

NYKnick101

It also could be how much service and sitting the car does. When I first got my is250, it felt rough because the engine oil hasnt been changed, differential oil hasnt been changed, other fluids, etc. When I changed all those fluids, it was like night and day difference on how much smoother the car drove and felt. Loaner cars get beat on as much as rental cars. When I'm in a rental car, I have that "Not my car, not my problem" mentality

Tarrant64

I personally was thinking that maybe you had it in ECT PWR mode and didn't realize it, which would give it that jerky type of response as it can be pretty touchy in that mode. I have the 350, drove a few 250s before deciding I needed more power and overall they felt similar. Obviously much more power with the 350 but my car does feel refined, I often feel like I'm holding it back trying to drive it normally. Perhaps it's just that you're not used to more powerful engines (not meant as an insult). I've driven a couple of powerful modded cars that my friends own and the 350 engine is amazingly smooth compared to theirs (one of which is an STI which is over 500hp but is so rough to drive).

jdmSW20

iTrader: (12)

i would have to agree with this comment. granted i never drove a 250, i have rode shotgun in one and i would have to say my 350 felt just as "refined" it just a great deal faster. but then again bigger motor i would expect it to be louder

JTK

Day 2: Some more feedback. I think the first few miles was when the car was adapting. It feels a lot better now, but engine note is more audible. Service intervals are 15K KM here and the car is on 14xxx, so perhaps it's due for an oil change/service, which is making the engine feel rougher than normal.

Played around the ECT power modes. I'm very, very impressed with this car's engine. Actually got me thinking of getting a used IS-F. I previously considered the IS250 as a relaxed family car and judged the range by that - the IS350 makes it feel a lot more like a sports car, the way the engine responds. This now got me thinking of getting an IS-F as my daily soon.