Five problems related to engine have been reported for the 1999 Toyota Sienna. The most recently reported issues are listed below.
I am reporting another Toyota sticky accelerator pedal. Our 1999 Sienna minivan has had 3 incidents of stuck accelerator, the most recent was Jan. 21, 2010. I believe it has become "stuck" between 40 and 45mph. Other incidents were in summer (cannot remember date) and October 2009. The 1st incident was brief and corrected quickly by pushing down on the pedal to "free it", the 2nd incident required braking and putting the car in neutral and shoving the pedal with my foot to the left and right to free it up. I was able to drive the car to the shoulder, turned the car off and then the pedal seemed to work ok, although a bit sluggish response. Our mechanic fixed the throttle body and the car has not had another incident until last week. The most recent incident was more harrowing in that there was not much room to maneuver the car since we were headed for lots of cars stopped at a traffic light. I tried to slow the car by braking hard with the left foot and shoving the accelerator. Pedal down and side to side while in neutral but this did not work quickly like the October incident. I was able to pull over to a shoulder before crashing but it took much longer for the car to stop this time, and I actually threw the car in park to stop the car! I turned off the car and after a few minutes, was composed enough to drive it. Our dealer will check the car Jan 29. The floor mat does not appear to be involved jamming into the pedal, so it is probably a mechanical "catch" that is getting hung up when the pedal is down a certain distance. We thought the safety gurus would want to know. Luckily no crashes have occurred yet!.
1999 Toyota Sienna engine froze up unexpectedly. Was advised it was possibly a sludge problem. This vehicle was purchased - used - in 2002 from a local dealer who will not accept any responsibility for the estimated $6850. 00 engine replacement cost, even though Toyota changed the engine warranty to 8 years/unlimited mileage.
Oil sludge (gelling) develops in engine resulting in the necessity to replace the engine at great cost. Toyota states that they will pay for the repairs if all required maintenance has been performed, but they have refused to do so and have refused to let us speak with anyone with the authority to honor their warranty.
My 1999 Toyota Sienna's engine suddenly froze up with slightly less than 72,000 miles on it. The engine is totally gone with estimates currently in the neighborhood of $8,000. This vehicle has been maintained as stated in the owners manual. The complaint is that Toyota knows there is a problem with Sienna's and has failed to do anything about notifying owners that oil changes need to be at 3000 mile intervals and that valves need to be checked very regularly. Since sludge build-up is obviously occurring in their vehicles, something needs to be done to protect the consumer.
The consumer believed Toyota was not honoring the customer support program as reported by owners, in regards to oil sludge build up in engines. Updated 05/04/10.