2002 Mitsubishi Lancer RPM in netral problem

With the engine OFF.
Remove the intake air snorkel from the throttle body. Use carb cleaner and a rag to clean the inside and outside of the throttle body.

(use more scrubbing with the rag than carb cleaner) Be sure open the throttle wide open so thay you can get to the edges of the throttle plates.

With the engine off, have a partner to press the gas pedal about half-way down and then let off of it gently, while you watch to see which direction it moves in to open and close.
1. Check the throttle underhood to see if it closes completely by pulling it in the CLOSED direction.
If it doesn't, remove the throttle cable from the throttle body and operate the throttle by hand (closing it gently to see if it closes completely. I
f not, the problem is either a weak, broken or dirty (jammed) return spring or misaligned throttle plate (causing it to rub against the side of the throttle bore - preventing it from closing) this can sometime be corrected by gently tapping on the side of the throttle plate pivot rod. (Be sure to remove the TPS first).

If the throttle does close complete in Check #1 the problem is in the cable. It is sticking of kinked/crushed. If the sticking point is close to the end (either end), often it can be lubricated and you can continue to use it. If it is corroded inside of its covering, replace it. Please post the result here. Thanks.