I have recently had the experience of my Transmission revving up to almost 4000 RPM while accelerating on the highway up to speed limit of 70 MPH. This is from a relatively cold start but lasted 30+ miles of highway driving where it it would erratically go from 2000 to 2800 rpm when going up any kind of road grade incline. And the running gas mileage was obviously down as well. Basically it was as if it would not shift into overdrive. I searched for an over drive off switch thinking my wife may have turned it off but found none nor no mention in the owners manual. After sitting at my destination for several hours and then leaving to go home it ran normal... averaging 2000 rpm entire way at 70 mph and got better gas mileage.

Question: Is this just an engine/trans warm up issue or should I consider having it looked at?

Anyone else have this experience?

 

How many miles on the transmission?

Have you changed the ATF (or added any)?

 

WOW, this is a first....

 

Derek, did you have colder than usual temps when that happened?

I've had Toyotas in the past that wouldn't shift into OD until the engine had warmed up.

 

This is NOT a first and this is TYPICAL behavior in cold weather, and more specifically, with a cold battery pack.

The car will go into intentional charge / discharge repeat.... cycles to warm the battery pack.

When the car is charging, the RPM's go up. When the car is discharging, the RPM's go down. My car does this for 4-5 minutes each cycle.

After the battery pack internal temperature gets over 50'F this behavior should stop.

The 2000 to 2800 swings can be explained by this.
The 4000 when accelerating ( assuming it is generally lower ) means you where accelerating with a cold battery, and there was reduced battery assist, and thus the engine needed to work harder.

Now... if it does this on a 75 degree day.... come back and we'll talk more!
-John

 

Only 20,000 miles... It was only on the first thing in the morning...30 degrees, run that it happened. It was strange because even with cruise control on it reved up and down like that. Traveling down the highway at 70 mph it probably didn't allow the battery to warm up either. What is the best way to quickly warm up the battery? I am only 1/2 mile off the highway that we take on any longer trip. I did buy a grill/radiator blocker but that wouldn't influence the battery temp right?

 

Did you read my first post?

Short of an OEM plug-in heater attachment,... ( 2005-2007's only )
The best way to warm up the battery is to use it.
The computer is using it MORE on a cold day, making your RPM change.
The RPM change is NOT hurting your MPG as much as you think.
Your MPG is lower primarily because it is colder outside.

-John

P.S. the car gets really strange at below zero Farenheight. You'll run 2000 RPM stopped at a stoplight!!!!

 

Actually it was 2-3 mpg less on the trip out while experiencing the fluctuations in rpms.
29.1 mpg at 70 mph vs. 31.9 mpg at 70 mph return trip relatively the same outside temp. only difference would be mid day warm up in between.

Where do you find the OEM htr. attachment?

 

Like the others have said, the engine revs higher when it's cold.

 

There were a couple things in your original post that nobody answered so I will.

Your transmission doesn't "shift" like a conventional transmission and it doesn't have an overdrive shutoff because there is no overdrive. In fact, there are no gears - it is a continuously variable transmission. Your engine speed for a given road speed sometimes seem like they have no relationship to each other and this is perfectly normal.

Best thing you can do is to just drive it and let the computer worry about what it is doing. The car is pretty darned smart and really manages engine speed and the batteries well.

You really want to see it act strange, go down a long hill with the car in "L" and watch the tach. Guarantee it will disturb you the first time it does what it does.