Im having an idle issue with my 03 lancer OZ. About a year ago, I started to have issue with the idle. When the car gets really warm after driving it for more than 30 min, the idle will start to go up when I come to a complete stop. I have to step on the brake hard or else the car will start rolling by itself. And then, when I put the car in neutral, the RPM goes all the way up to 3000 and stay there till I put the car back into drive. Need help please. The car is automatic by the way.

 

It's your throttle cable. When the cable sheath gets warm it gets pliable and the throttle cable inside gets stuck. So your throttle body is staying open with the cable getting stuck. Replace your throttle body cable and consider covering it with a heat resistant material on the area that goes over the valve cover/exhaust manifold.