Not sure what this is.... 1997 328 i convertible 123,000 miles. Sitting at a red light in Drive. The car all of a sudden felt like it was going to move forward, almost like a jerking but my foot was on the break and the car didn't move. It doesn't do it all the time. Another example was getting on the highway and it was stammering, another words not getting up to speed and then all of a sudden it kicked in. Can someone explain this to me?