I am trying to make an Ai that works for a scrolling map in a racing game that takes a certain line, how do i do that (its top down btw)

Depends on if the player can interact with the bot. If the player and the bot are independent, then you can just record your own inputs while playing the game, then use them in the bot.

If the AI isn't going to be able to have collision with the player, then you should just record like -TUB- said. If the AI is able to collide with the player then I would recommend using a way point system, they are a bit complicated but I've found them to work well so far.