A production plunger that automatically reciprocates in a production string of a well to remove formation fluid from the well. The production plunger makes a sealing contact with the production string and includes a passage through which all formation fluid is caused to flow through. The passage includes a valve that operates automatically in response to pressure within the production string to open and close the passage to allow and stop formation fluid from flowing in the passage. The plunger includes a locking device to ensure the plunger does not short cycle and a fail safe mechanism ensuring the valve closes in case of plunger failure, or upon a minimal build up of pressure by shutting in the well. Further, the entire valve is enclosed in the plunger preventing damage to valve elements from impacting downhole equipment, and the plunger includes fluid ports positioned so as not to easily capture well solids.