4 Pin RGB LED Flickering Flame effect, help!

Using Arduino LEDs and Multiplexing
2

To keep the light in the Red/Orange/Yellow range you probably want to make sure that the Green and Blue components are the same intensity:

int ledPinRed = 10;
int ledPinGreen = 9;
int ledPinBlue = 11;

void setup()
{
pinMode(ledPinRed, OUTPUT);
pinMode(ledPinGreen, OUTPUT);
pinMode(ledPinBlue, OUTPUT);
}

void loop() {
int Red = random(120)+135;
int Yellow = random(120)+135;
analogWrite(ledPinRed, Red);
analogWrite(ledPinGreen, Yellow);
analogWrite(ledPinBlue, Yellow);
delay(random(100));
}