Vehicle has extreme stuttering when driving at high speeds on the interstate.

- Westerville, OH, USA

I was driving my car on the way back from a trip, about an hour away. While driving about 70 MPH on the highway, my car started to feel like it was lurching forward, and the RPMs started shooting up and down uncontrollably. I tried to write it off as faulty cruise control or the shoes I was wearing, so I switched both of these things. Finally, the RPM shot up to 7000 without warning or cause. I drove 45 mph the rest of the way home as to ensure my safety. No dash lights or warnings had been given to signal that something was wrong with the car. Upon getting pretty close to home, I stopped at a red light. My car sounded as if it had shut down. The light turned green, and despite pressing the gas, the car did not move. Only at this point did the battery light and oil light come on. After restarting the car, no lights remained, and I was able to continue home. I took it to a private mechanic, who stated that he could not recreate the problem but that he believed it was a transmission issue. He advised I take it to Hyundai, which I did. They also told me they drove the car and could not recreate the issue. I was assured my car was fine. Despite this, every day I drove to work or school, I could feel my car doing the same thing. It seems as if every time I tried to maintain speed, the RPM would shoot up and down uncontrollably and gain speed on its own. Finally, as I was returning from a friend's apartment, every time I hit the brakes, I could feel my car sputtering, as if it was about to give out. When I would try to accelerate, I would have to use a lot of pressure on the acceleration to get the car to even go, and it could not gain speed. Once stopped, it was incredibly hard to get the car to move at all. Luckily, I was only a few minutes from home, as if I was much further, I do not believe I would have made it.

- Chatham, IL, USA