At a cold start early in the morning the car idles at 1500 and proceeds to 2000 after driving it. Rolling in neutral it stays at 2000 until I come to a complete stop where it falls back down to 1500. This is consistant in the morning when it is cold, but sometimes in the after noon or after it has had a chance to warm up and I start it up it barely starts(with a full tank of gas), and when it does, if I don't gas it it will fall so low it cuts off. I try pumping the gas 4 times before I start the car and giving it a good stomp once it has started, but this only works 75% of the time. Any ideas on why this is happening?