My car will start but will then stall in cold weather. 92 honda prelude?

ok. so i got a 19992 honda prelude that when i start it in the mornings, or anytime its cold it will start rev up to 3 and then as it comes back down it just keeps coming down and turns off. i dont know why. but then i start it again and the same thing will happen unless i put my foot on the pedal and hold it at 3 rpms until it is warmed up enough usually after 30 seconds. but like i got new spark plugs, what could be wrong with it.