MQ4 gas sensor is not working with Arduino UNO
That is what I would expect to see with one of these sensors.

I'm not sure on the wiring, I think you may be wrong.  Have a read of http://playground.arduino.cc/Main/MQGasSensors#readdatasheet and see if you agree.

Did you leave the sensor to warm up?  It takes a few minutes (from memory) and until its warm it won't give you a proper reading.

An MQ4 should be able to detect Methane, butane and propane, so was your lighter using on of these gasses?  When it does detect the target gas, the number will go up, and stay up for a while.

Another thing you can try is blowing on the sensor, the results will vary depending on what you have been eating, but it should shift one way or another.  

If it still doesn't work then buzz out your connections, just to triple check, and re-read the manual.