Leaking may occur due to debris getting under the diaphragm and preventing it from seating properly and creating gaps which allows air to pass. This could be caused by having a dirty air environment or by having inadequate filtration. You should first check the regulator to ensure that the diaphragm is clean and undamaged. You should also make sure that you have an adequate filter upstream and then consider changing the filter element. Dirty air and debris in the system can also cause the diaphragm to tear in which case you would experience the same performance issues. The diaphragm can be easily replaced by purchasing a repair kit.