This cleo allows every engine in San Andreas (except air vehicles) use the same function used in Grand Theft Auto IV.
Usually when you press F a single time the player gets out, if you hold F for a brief time the player gets out and the engine shuts down.
This script allows you to do this in GTA San Andreas.
Intructions in the readme
Bugs and Glitches
If your computer is really slow, there's a high chance that the engine will shut down every time you press F.
Apart from this the rest is OK.