Bplus, you also might want to slow it down. I've seen before on my stuff that your computer might run faster than mine for some reason. You can slow down the _LIMIT or you can reduce the numbers that x, y, ex, ey, ex2, and ey2 move every loop. They are set on 5 right now I believe. The car is easier to control slowed down I've seen. _LIMIT is set at 1000 on line 10.
Note: I made an update that changes speed as you like it on a post below.