About once a month, my car will idle roughly when I start it and then it will stall. Feeding the car gas will do very little to stop it from stalling. It will do this for about 3 times then it will take off like nothing ever happened. And only does it when the car is warmed up. Does not throw a check engine light when it does this. But I do manage to get a check engine light about once a month. Gives me 8,9,15, and recently a 20. Any thoughts?