Arduino Bluetooth Car

//includere predirective
#include <AFMotor.h>
#include "DHT.h"
#include <Wire.h>
#include <LiquidCrystal_I2C.h>
#include <IRremote.h>
#include <NewTone.h>
//definire iR buttons
#define btnZero 39015
#define btnUnu 41565
#define btnDoi 25245
#define btnTrei 57885
#define btnPatru 8925
#define btnCinci 765
#define btnSase 49725
#define btnSapte 57375
#define btnOpt 43095
#define btnNoua 36975
#define btnUp 6375
#define btnDown 19125
#define btnLeft 4335
#define btnRight 23205
#define btnOk 14535
#define btnStea 26775
#define btnHash 45135
// sfarsit iRbuttons
int IR_PIN = A1;
#define DHTPIN 2
#define DHTTYPE DHT11
AF_DCMotor rightR_motor(4, MOTOR12_8KHZ);
AF_DCMotor leftF_motor(2, MOTOR12_8KHZ);
AF_DCMotor leftR_motor(3, MOTOR12_8KHZ);
AF_DCMotor rightF_motor(1, MOTOR12_8KHZ);
IRrecv irDetect(IR_PIN);
decode_results rezultat;
LiquidCrystal_I2C lcd = LiquidCrystal_I2C(0x3F, 16, 2);
DHT dht(DHTPIN, DHTTYPE);


int buzzer = 13;
int gaz = A0;
float slope = -0.318;
float y_intercept = 1.133;
float R0 = 11.820;
String readString;


void setup() {
  rightR_motor.setSpeed(1000);
  leftR_motor.setSpeed(1000);
  rightF_motor.setSpeed(1000);
  leftF_motor.setSpeed(1000);

  lcd.init();
  lcd.backlight();
  dht.begin();
  irDetect.enableIRIn();
  pinMode(buzzer, OUTPUT);
  pinMode(gaz, INPUT);
  Serial.begin(9600);

}

void loop() {
  while (Serial.available()) {
    delay(5);
    char c = Serial.read();
    readString += c;

    if (readString.length() > 0) {
      Serial.println(readString);
      if (readString == "F") {
        rightF_motor.run (BACKWARD);
        rightR_motor.run (BACKWARD);
        leftF_motor.run (FORWARD);
        leftR_motor.run (FORWARD);

      }
      if (readString == "B") {
        rightF_motor.run (FORWARD);
        rightR_motor.run (FORWARD);
        leftF_motor.run (BACKWARD);
        leftR_motor.run (BACKWARD);

      }
      if (readString == "R") {
        rightF_motor.run (RELEASE);
        rightR_motor.run (RELEASE);
        leftF_motor.run (FORWARD);
        leftR_motor.run (FORWARD);

      }
      if (readString == "L") {
        rightF_motor.run (BACKWARD);
        rightR_motor.run (BACKWARD);
        leftF_motor.run (RELEASE);
        leftR_motor.run (RELEASE);

      }

      if (readString == "S") {

        rightF_motor.run (RELEASE);
        rightR_motor.run (RELEASE);
        leftF_motor.run (RELEASE);
        leftR_motor.run (RELEASE);
      }

      if (readString == "V") {
        NewTone(buzzer, 1000);
        delay(500);
      }
      if (readString == "v") {
        noNewTone(buzzer);
      }
    }
    readString = "";
  }
  gasDetection();
  int h = dht.readHumidity();
  int t = dht.readTemperature() ;
  int f = dht.readTemperature(true);

  lcd.setCursor(0, 0); // Set the cursor on the first column and first row.
  lcd.print("Temp: "); // Print the string "Hello World!"
  lcd.print(t);
  lcd.print(char(223));
  lcd.print("C");
  lcd.setCursor(0, 1); //Set the cursor on the third column and the second row (counting starts at 0!).
  lcd.print("Umid: ");
  lcd.print(h);
  lcd.print("%");


} //end loop
void gasDetection() {
  float sensor_voltage;
  float RS_gas_resistance;
  float ratio;
  float sensorValue = analogRead(gaz);
  sensor_voltage = sensorValue * (5.0 / 1023.0);
  RS_gas_resistance = ((5.0 * 10.0) / sensor_voltage) - 10.0;
  ratio = RS_gas_resistance / R0;

  double ppm_log = (log10(ratio) - y_intercept) / slope;
  double ppm = pow(10, ppm_log);
  double percentage = ppm / 10000;

  Serial.println(ppm);
  if (ppm > 10) {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Detectie gaz!    ");
    lcd.setCursor(7, 1);
    lcd.print("Con : ");
    lcd.print(percentage);
    lcd.print("%");
    NewTone(buzzer, 500);
    delay(1000);
  }
  else {

    noNewTone();
  }
}//end gasDetection

Using the code posted above, i encounter a strange problem.More exactly, one of the motors won;t run.
3 motors are running but the motor 1 does not spin . So.. my question is... does anyone know why(looking at the code- is there something that i don't observe>?
Thanks in advance

You don't have a "motor 1", you have "rightF_motor, rightR_motor, leftF_motor, leftR_motor". Which is it?

And are you actually using an old Adafruit Motor Shield V1? That's what AFMotor.h is intended to work with.

Steve

Agree with you but i declared one pin to each side motor. So the motor no1 is assignated to rightF_motor.