I have installed simple native trainer, and it works fine, when I disable key Binding in the config file, it says in game "no car found" and the trainer is really slow at responding how do I fix this?

Either the car your trying to spawn or a keybinding is making a car spawn, and it's either has no handling line added (Like Police 3 with a custom handling line) or your computer is lagging (Usually texture loss) so it can't spawn the vehicle.