My car will start and immediately turn off unless I give it gas at the same time

Hello, You are likely experiencing the idle air control valve failing. The idle air control valve is meant to allow air into the engine while the gas pedal is not pressed. This prevents it from shutting down in this manner. You will likely need a professional diagnosis, but you can also try to clean the idle air port in the throttle body. I'm sure there is probably a lot of gunk built up in there. Let me know if I missed anything, or if you would like additional information. Otherwise, here is a link to certified services in your area: http://repairpal.com/nissan-within-10-miles-of-tallahassee-florida-32303