When u start my car it idles for a second then idles lower and then dies.

What is your question?

Sometimes I have to throw it in gear and step on the gas to get it going and then it usually doesn't give me problems again. Well it just took me 5 or 6 times in the parking lot to get it started and get going to make it to work. What could the problem be? Also sometimes when I turn the ignition off and take out the key the engine doesn't die down for about 5 to 30 seconds, it just depends.