2003 Chevy Malibu starting problems

I did check the plugs and they do have spark. When the car turns on, it runs real good. This problem only happens about once a month.I have read about the similar problems other have had with these malibus.I drive it. It runs fine, and if I go to the store for example, and get back in to start the car, the motor turns but will not start.I do remember the theft system light blinking for a while, on one occasion I was driving the car. Do the keys on these cars have chips in them, I can not tell by looking at the key.

Just today sunday my car acted up again, I did as you told me about the ten minute key on acc so the computer could relearn the key and it worked, thanks a million. You saved me time from tearing into my relays to the gas pump, which is what I thought was the problem. Next question is can I bypass the security system by rewiring the key switch, I have knowled in the electrical parts in cars.