Bought an 06 IS350 about a month ago. The car has 92k miles on it. The last couple of weeks, I have noticed the car starts revving high at times. Most of the times it's when decelerating. It's done it a few times while sitting at a red light. The RPMs increase about 1000 RPM. Today, I was going down a hill and it jumped up to 3500 RPM. Any previous V-6 cars (non-Toytota/Lexus) I have owned have never done this. Is this something normal with this engine or is there any issue? The sudden jump to 3500 RPM really got my attention.

When you are going down a hill, the car will downshift to use engine compression to slow you down to save your brakes, this is a good thing. No different than if you were driving standard and down shifted for a hill.

I can see that. But is 3500 RPM normal?

Totally, that isn't high at all. Now because the ECU learns driving habits, everyone's car will behave a bit differently, but here's roughly what mine does. If I am going down a hill and touch the brakes, it will downshift to assist in decelerating. It could easily go above 3500 RPM. Now, If I hit the gas, it will wait a second to see if I am being aggressive or if I am just back to cruising and then it will shift up if I am just cruising. This is actually a really nice feature and was one thing I thought I would miss by not driving standard anymore.

Are you in "PWR" mode or "Normal"?

Me? I'm in normal mode.

The car automatically downshift and hold the lower gear when you go down hill. This happens often when you tap the brake lightly. It is designed this way and totally normal.

I drive my cars hard almost everyday and they run fine for years as long as all the maintenance is taken care of.

Like everyone said it is totally normal, mine does it too. It is a good feature and makes me feel that little pull like i'm driving a manual car .

You can do an ECU reset so the car learns your driving style, maybe the previous owner drove the car more aggressively than you. Search the forums for an ECU reset thread.

Thanks for all the responses.

When I drive downhill usually through hills and tap the brakes, I experience a dramatic down shift from the 6th gear to the 4th leading to 4000 RMP and sometimes it takes a while to shift back up, so what i do now is when it happens, I switch it to manual shift and shift back up to 5th and 6th gear. Is this normal?

Yes. 10 chars.

Why don't you like it downshifting? Why not just let the car do what it wants to do?

The paddle shifter cannot really shift up to 5th and 6th. It still probably stays in 4th gear even though your shifter shows it at 5th or 6th because shifting up is all controlled by the automatic transmission. The manual shift is only a gear limiter.

Actually, it may upshift to 5th or 6th. Don't quote me on this, but when in manual mode, the transmission won't do the special downshifts and what not that it would in auto.

That could also be the case due to the automatic transmission decide to do so, not really because of the paddle shifting up.

You can put in manual mode at 6th gear and the auto transmission shift up and down automatically all day long. That is why I don't like this fake paddle shifter much. I wish it would be a true shift up and down depending on your choice and not the tanny.