Computer problem
2002 Chevy Malibu 6 cyl Front Wheel Drive Automatic 120000 miles

At times I will try to start the engine and it won't start. The theft light will be blinking. I can leave the switch on for about 15 minutes and the theft light will stop blinking and the car will start. Any idea what is causing this and is it something I can repair or will I have to take it to a dealer??

you need a pass lock sensor. if you know how to work on cars, you could do it your self. you already know how to program it. "leaving the key on for 15 min"