2009 civic sdn stalls
 

Car fires up easily. Runs two seconds and shuts down. Pressing accelerator pedal does increase rpm briefly. Must turn off the key to restart. It will not start by simply turning the key again. It was running fine when I parked it. Car sat for 3 days in single digit temps. I added two cans of dry gas and a can sea foam with no improvement. The check engine light is not lit.

It sounds like a fuel system issue.
Turning the key to the on position will prime fuel rail for about two seconds.
Engine will start and then die cause the fuel pump isn't running while engine is running.

Would check fuses and relays to the fuel pump
Don't forget to look at pin sockets to see if there is corrosion??

Hope this helps