whats the reason my cars getting to much gas?

What is your question?

I have had problems starting my car i changed all the filters and spark plugs and wires and i know there is a spark. I also did a complete oil change and replaced the starter due to it burning out when i tried to start my car to many times in arow. It seems as if when the key is turned the gas continues to flow without stopping until the key is turned off, it back fires from time to time when i first try to start it ude to excessive fuel. what could be the cause of this?