4 blinks is open limit circuit so if it comes back on by itself then it is the main limit tripping. This could be caused by a few things that effect your airflow through the furnace.
Dirty evaporator coil
Malfunctioing blower motor
a stopped up heat exchanger
or a malfunctioning limit
This limit senses the temperature inside the heat exchanger and it the air is not moving across this heat exchanger suffeciently it will trip this limit until the blower gets the heat exchanger cooled down then it will allow the burners to ignite again or you have to manuyally turn power on then off to reset the limit. All of these other issues should be addressed before replacing the limit because if there is an airflow issue then the new limit will just do the same exact thing this one is doing.