[Mean]

pawn Код:

new vehicleid = GetPlayerVehicleID(playerid);
new engine, lights, alarm, doors, bonnet, boot, objective;
GetVehicleParamsEx(vehicleid, engine, lights, alarm, doors, bonnet, boot, objective);
if(engine == 1) {
    // ENGINE IS RUNNING
}
else {
    // ENGINE IS NOT RUNNING
}

You can use #pragma unused to eliminate the variables you didn't use, such as lights, alarm, etc.