Sample Car Following

So right now I'm trying to use unity's sample car in my game. I'm tweaing it and changing to suit my needs and it works fine for the most part but now I need the car to follow another one, and for that it lacks precision. Right now I changed breaking condition to "Target Distance" and it slows down but doesn't maintain speed and when it goes too far front it turns around. I tried tweaking the values, but I just couldn't make it work, especially when target that it's supposed to follow changes speed. So, can anyone help me with this, because, honestly, right now I dont even know what to look at.