The contact owns a 2000 Hyundai Sonata. While driving approximately 45 mph, the engine began to rev excessively high and the vehicle lunged forward unexpectedly. When the accelerator pedal was depressed, the vehicle hesitated and vibrated. In addition, the automatic transmission shifted violently into gear. There was no power response during acceleration, which resulted in the engine stalling intermittently. The warning indicator also illuminated on the instrument panel intermittently. The vehicle was taken to an authorized dealer for inspection, but they were unable to duplicate the failures. The mass damper was replaced. The vehicle was taken to an authorized dealer on six separate occasions for identical failures. The repairs consisted of a complete tune up, replacement of the "output" speed sensor, and the battery was replaced twice; however, the failures continued. The extended warranty on the vehicle expired at 60,000 miles. The vehicle has not been repaired. The failure mileage was 13,559 and current mileage was 82,505.

- South Mills, NC, USA

Transmission input speed sensor failure, this problem is shockingly all over the internet, the sensor fails and if your on the highway, you suddenly slam down in speed to almost half your previous speed with a loud bang as the transaxle jumps from 4th gear to 2nd gear and the engine redlines. Due to the failed sensor telling the transaxle to downshift improperly. A inexperienced or less capable driver may have been thrown out of control from the sheer force of the impact when the transaxle mis-shifts from 4th to 2nd when the sensor malfunctions.

- Tempe, AZ, USA

I have a 2000 Hyundai Sonata. When the car was first purchased in February of 2006 the car had transmission problems where the car would not accelerate past 25 mph. I had to have the transmission replaced. Then later in that year while driving on the highway at about 65 mph I noticed the car would sway dramatically when you turned the will right. Taking the car back to the dealer they claimed to be just that the car needed an aliment. Now in 2008 I have had to have the right axle of the car replaced because while pulling away from a stop light the right wheel fell from the car at a 45 degree angle. Taking it to a tire shop to have the car inspected they informed me that the whole front underside of the frame was drastically rusted and that driving the car in the state would lead to a wreck or worse. Now I am lost and don't know what to do I have done research on the problem and I have found over 20 reports of this car model having this problem and it is very upsetting that no recall has been placed on these death traps on wheels. Someone needs to take responsibility for this before some dies.

- Basehor, KS, USA

Car stalls out in low speed driving, idling, and or when back up. I have been able to avoid an accident with passengers in the vehicle or not in the vehicle while I was driving. I have had oil changed, fluids checked, alternator changed, spark plugs and wires also checked. The car has also had fuel system flushed and problem with stalling persist.

- West Warwick, RI, USA

The contact owns a 2000 Hyundai Sonata. The contact has been experiencing failure with the sensor plug on her vehicle. She has had to pay $200 each time the vehicle has been repaired. She stated that she is also experiencing failure with the powertrain automatic transmission, which caused her vehicle to stall. She has had to replace her engine and the battery approximately two to three times. The powertrain was unknown. The current mileage is 118,000 and failure mileage was 67,000. The consumer stated replaced the engine 1 time and the battery twice. The dealer stated radio jumping channels. Updated 09/05/07

- Hephzibah, GA, USA

Car had a recall for the oxygen sensors and was taken care of. However, it has been in the shop 3 other times to have the oxygen sensors replaced and I just had another go out past the warranty period. I have also had the car 'slam' into a lower gear while on the expressway and the check engine light came on. When I take it they say it is a transmission sensor and replace it. This has done it five times!! it is very scary when it does this. The car is on it's fourth battery and it has 80,000 on the odometer. I have had numerous other problems too. Now it just will not start, it is going to an independent shop this time. This car has been one big headache!!!

- Florence, KY, USA

While driving wheels locked as if the consumer was jamming the brakes. Transmission was replaced three times, but vehicle slowed down on its own. Then, vehicle accelerated without the pedal being depressed.

- Canada, 00, USA

My 2000 Sonata stalls and or flutters intermittenly when shifting from first to second and sometimes from 2nd to third. Transmission was replaced but still is doing the same thing. It has been in the the service department many times but I am told "nothing is wrong with it" there was a loud clank when shifting gears even when parked. One of the main rep from Hyundai came and checked it out and said it was fine. He also drove the car, but the way he drove it was like at being at an indy 500. I asked him to compare my car with any other car on the lot to see if the noise was normal, he refused. I took the car to another Hyundai dealer and was told the car was unsafe to drive because 3 bolts had backed out of the housing thus causing the clanking noise. It still flutters. I have been dealing with this problem since 11-2001. I bought the car in 3-2000. New. The sensor also had to be replaced twice.

- Fairfield, CA, USA

There was an erratic operation when the accelerator pedal is applied. The dealer could not duplicate the problem. The horn malfunctioned, the door(s) closed by themselves, and when the vehicle was driven pass the 40 mph mark, the transmission operated as if were catching up. Scc

- Port St Lucie, FL, USA

Consumer states that while driving vehicle will not shift correctly. Caused by transmission failure. Had it replaced 3 times.

- Ravenna, OH, USA

While driving and upon acceleration, vehicle remains in drive, but does not accelerate properly. Vehicle shifts into netural, at times becoming stuck in between gears. Cause unknown.. consumer stated when vehicle is moving to shift from low to high it sits in between gears and makes a loud noise, the vehicle has been in the shop on several occasions and the transmission has been replaced twice, dealer stated there is no problem.

- Hoover, AL, USA

The airbag light comes on. The district manger, jeff westland out of N.J., (609) 395-7308 stated that Hyundai is aware of a defect in the right passenger seat (late 1999's & early 2000's that rolled off the assembly) which makes the light come on if a person moves around in the seat, excessive weight of a passenger, or putting any object under the seat. What I find outrageous about this, is the last two times I've taken my vehicle in, I've been told that the airbag light was not on. When I spoke with Mr. Westland, he wanted me to leave the car for several days at the dealship, first team, so they could go over it bumper to bumper. On January 8, 2001 I took the car into the dealer so they could look at the transmission and the airbag light which was on again. On that evening, at approximately 5:00, I received a call from the dealship, asking if I could come into the dealership the next morning to drive with one of their mechanics because they could not duplicate the problem with the transmission. I was unable to do so because of work. I was also told that the airbag light had not been on. I picked up the car that evening since, "nothing was wrong with it" and would be unable to test drive it with a mechanic.. I do not understand why the dealership is saying that the airbag light has not been on the last several times when it has been. The transmission sporatically downshifts when I am driving on the freeway on a straight and level surface at a constant speed. It also hesitates sometimes when starting off from a dead stop. If you would like any of the invoices stating the repairs that have been done to these two problems, please contact me. Thank you for your help.

- Chesapeake, VA, USA

Vehicle stalls when low in a gear, sounds as if it is a vibration problem related to map sensor as recalled on the 2.6L Sonata and the elantra models.

- Newbern, TN, USA

If accelerated up to 45mph speed slowed down, and consumer had to release the speed, transmission was stalling. Vehicle has been in the shop several times. Dealership has been notified.

- Los Angeles, CA, USA