Car shuts off after turning it on?

2006 subaru impreza wrx sti with about 49k miles. no check engine lights. when i turn on the car, the rpm dips super low and the car shuts off. i could turn on the car and gas it so the rpm stays high for about 10 seconds then the car will idle and drive perfectly fine.the only issue is during the start up. any ideas of whats wrong? any advice will help. thakns.