I was driving North out of phoenix Arizona on I-17 just past black canyon city, with my cruise control set at 75 mph. There is a very long hill going North to sunset point. Prior to approaching the hill I canceled the cruise so that the transmission wouldn't hunt gears. I drove up the hill at 65 to 75 mph (no cruise). When I made the top of the hill at sunset point and leveled out, I accelerated the vehicle to 75 mph and hit resume. The engine raced to 5200 RPM. I redline at 5700 RPM. The transmission did not follow suite. It was as if I was in neutral revving the engine. I immediately canceled the cruise and drove a mile or so without cruise, then decided to try it again. Everything worked normal. I have been in contact with my dealers service dept. And they are baffled. They have not looked at it as yet due to their schedule. As soon as they can get me in they will. They did say that there should have been a check engine light, but there was not. They are hoping that the onboard computer recorded it. Not only is this a major safety hazard, but it could have caused my engine to blow up. I'm not sure what reaction my wife would have had. She drives all the vehicles we have and they both have cruise, yet she is not that familiar wit RPM's and redlines and the issue that follow. When I have allowed the cruise to pull me up an incline it usually drops 1 or two gears and the RPM's are around 3000 to 3200. This I consider normal. I had a 1999 Toyota Tacoma with a six cylinder engine and cruise, so I am very familiar with the system. I purchased the vehicle from tim's Toyota in prescott, I also brought to their attention a noise that I heard in the right front suspension and they are going to take care of it under a new recall that has not even been sent to customers, nor was the service dept aware of it.

- Prescott, AZ, USA

With cruise control engaged at 55 mph any increase in incline will initiate a one or two gear downshift and substantial throttle application. Also when in cruise control using hand control stalk to increase speed slightly will initiate a one or two gear downshift and substantial throttle application. Both of these situations can startle the driver because of the abrupt changes and could cause an accident leading to injury/death.

- Moun Morris, NY, USA

2006 Toyota Tundra:when cruise control is engaged, any hill or even minor incline initiates a downshift of one or two gears accompanied by full throttle acceleration does not occur, even on major hills sans cruise control. Dealer says this is normal. Action should be taken before an accident/death occurs.

- Chester, VA, USA

Ltr from (tx) reporting problems with his 2006 Tundra motor vehicle. The cruise control has a problem down shifting 2 gears on minor grade for no reason, which caused the engine to rev to over 4000 rpms. The vehicle would not shift into overdrive while driving on the freeway. The brake will fade while sitting at a traffic light. The stopping distance on the vehicle was much longer than any other vehicle the consumer had driven. The vehicle was getting very poor gas mileage. There was an odor from the air condition. The tire sensor light illuminated, but it was resolved.

- Conroe, TX, USA

2006 Tundra - have had truck only 2 weeks and took road trip. When using cruise control and starting up a modest hill vehicle will kick down from overdrive into drive, even though w/O cruise vehicle can handle hill fine in overdrive. This will bring rpms from 2000 to 3000. This is merely annoying. Sometimes will kick down past drive and into 3rd gear, bringing rpms to 5000 and cause the vehicle to accelerate rapidly on hill. This seems unsafe, especially in crowded or wet conditions. Have found numerous complaints from other Tundra owners online. All say dealer and Toyota claim this is "normal." Toyota corporate office told me they consider this "normal" and recommend I not use cruise control in hilly areas. Must not have hilly areas where Toyota engineers live.

- Alexandria, VA, USA

2006 Tundra 4 door overspeed when driving in cruise control. When driving at highway speed with cruise control on and approaching a slight incline, the vehicle will drop into passing gear and the throttle will go to full throttle. This will cause the operator to lose control of the vehicle, especially on a rain slick road. This has happened many times, and although I am aware that it could happen, it still startles me when it occurs. If close behind another vehicle, this could lead to an rear end accident. The normal progression should be dropping out of overdrive, with a gradual acceleration to maintain set speed, and then back to overdrive when set speed is obtained. Dealer called Toyota and they claimed this is normal operation. Documented with Toyota dealer, and now with NHTSA. When accident occurs as a result of this overspeed, hopefully Toyota will reset the computer control module to fix problem.

- Deland, FM, USA