2005 Toyota Sienna. Consumer states problems with transmission response. The first encounter the consumer had with the dealer with regards to the transmission was poor programming. So, the dealer re-calibrated the ECM. However, the transmission continued to hesitate before shifting up or down. The problem was most noticeable when slowing down.

- Tucson, AZ, USA

The vehicle exhibits unpredictable acceleration. When the acceleration is pressed there is a delay of several seconds before the vehicle responds resulting in an unsafe situation.

- Chestnut Ridge, NY, USA

The contact owns a 2005 Toyota Sienna van. The failure mileage was 700 and the current mileage was 51000. There is a transmission delay with his vehicle that is constant, and occurs when driving between 6-10 mph. The dealer called it hunting for a gear. The vehicle has been to the dealer 6 times since a month after purchasing the vehicle for this problem; however the dealer has been unable to repair the vehicle.

- Burbank, SD, USA

2005 Sienna le auto transmission will not downshift properly at slowing / low speeds. Feels like shifts into neutral at times. Has been checked by dealer every 5,000 mile oil change with same answer - nothing found.

- Rehoboth, MA, USA

Toyota 2005 Sienna mini van xle fwd - accelerating from low speed roll (around 5 to 10 mph) the car essentially experiences a stalling condition where it will not accelerate for a few seconds. More gas pedal depression results in a sudden occasionally almost uncontrollable acceleration.

- Gaithersburg, MD, USA

Hesitation when downshifting to 1st, then when trying to accelerate it feels as if nothing is going to happen so you give it more accelerator and then it accelerates too fast, mostly noticeable as you turn a corner.

- Mcallen, TX, USA

: the contact stated the vehicle had difficulty switching gears and caused acceleration issues. The service dealer stated the computer system adjusted to the driver and this was a normal function. However, the contact stated the gears did not shift properly. Updated 10/18/2006 - the vehicle would hesitate when picking up speed. The check engine light illuminated. The dealer found code for evap purge valve. The technician found the vacuum lines off at intake.

- Dyersburg, TN, USA

I have a 2005 Sienna.since I bought it, transmission is jerky, sticky, jumpy and erratic transmission movement when you suddenly stop and try proceed. Visited dealer four times recalibrated twice. Now not only original problems persist in addition transmission shifts make a loud noise.

- Tallahassee, FL, USA

Automatic transmission failed and car could not be moved out of traffic.

- South Bend, IN, USA

As we exited the dealership after purchasing the 2005 Toyota Sienna van, the transmission seemed to slip as it downshifted into a slow turn. This happened so many times with various drivers that we contacted the dealer. Some five trips and weeks without our vehicle, the dealer couldn't fix it. They also experienced the problem and would contact the Toyota rep. More visits and calls and no repair. The dealer said the transmission was getting used to the primary driver. Dealer seemed to doubt our credibility, but has agreed to either fix it or "convince us that this is the way a 2005 Sienna van drives." After reading the numerous complaints just like ours, I doubt that Toyota can fix this. Computer was reprogrammed and fluid changed--made it worse. We give up. We note that the 2006 Sienna has not received any complaints like this.

- Dyersburg, TN, USA

When accelerating from 5-10 mph, van hesitates and then jerks forward trying to find correct gear or catch up. This is especially dangerous on snow/ice. Took to local dealer 3 times and was told all of Toyota's 5-speed transmissions do this and my Sienna wasn't as bad as others. The dealership did reprogram computer and I could tell no difference. I was told there was nothing else they could or /would do. I complained to Toyota headquarters and still got nowhere.

- Indianapolis, IN, USA

On my 2005 Sienna xle limited AWD, I have noticed at 50+ miles an hour interstate or even downhill) that the car feels like there is excessive rolling resistance, and if I don;T accelerate, very soon it downshifts (have noticed this even on a downhill slope at 45 miles a hour). Service advisor said all Toyota cars as designed to downshift as soon as you take your foot from the pedal (something which sounds very strange to me, since I'm driving other makes and models as well). Seems the transmission is not tuned well. On a separate matter, I noticed several times that the car hesitates to accelerate for a few seconds when I push the accelerator a bit harder at very low speeds, such as when I need to merge into heavy traffic from a side road. It also happened when I needed to change the lanes from a very slow moving lane to one where I needed to accelerate rapidly. Again, something feels wrong about the transmission.

- Colorado Springs, CO, USA

: the contact stated while driving 15mph or less, the automatic transmission shifted into neutral. Although the gearshift was not visibly seen changing gears, the vehicle was physically felt shifting down and loosing momentum. The vehicle was seen by the local dealer. The dealer reprogrammed the computer, but the problem persisted. The dealer was unable to determine how to remedy the problem.

- Key West, FL, USA

Contact owns a 2005 Toyota Sienna. The vehicle has severe hesitation, almost impossible to drive the vehicle on a wet road or on a snowy road. Gas pedal and transmission do not seem to connect. No crashes. No police reports. No fires. The vehicle has been to Toyota dealer 5 times; the mechanic came back and said they found nothing wrong with vehicle. (11/08/05) the transmission would down shift very harsh on turns and on hills. The service dealer placed an upgraded computer in the vehicle but the problem worsened.

- Hampton , TN, USA

Hesitation when accelerating. Particularly when already rolling at less than 5 miles an hour.

- Danville, CA, USA