Q: my car starts and dies right after startup before I gear into drive. it doesn't always just occasionaly.

I turn my key in my 2006 Pontiac Grand Prix, and most the time my car starts. Occasionally it will turn over, and then turn off. A second attempt and it usually starts right up, it idles roughly always. If i giive it gas when i turn the key ot will start always. Sometimes it leaks oil from the back of the engine, I can't pinpoint the location. Occasionally it will leak alot but mostly doesn't leak much. Sometimes it won't leak at all. It drives fine mostly, any advice?

My car has 149500 miles.
My car has an automatic transmission.