[DJDhan]

Код:

new CarFuel[MAX_VEHICLES]; // no need for initialising

Also, it should be a float.

Код:

new Float:CarFuel[MAX_VEHICLES];

because are not decreasing whole numbers but decimals in your "Fueldecrease" callback.

Either decrease whole numbers, or use float and while printing :

Код:

format(String,sizeof(String),"~r~Fuel~g~:~p~%0.2f ~r~MPH~g~:~p~%i ~r~KMH~g~:~p~%i",CarFuel[vehicle], floatround(floatdiv(Speed, 1.609344), floatround_floor), floatround(Speed, floatround_floor));