My pneumatic nailer / stapler will no longer drive the fastener completely; it seems to be losing power. Can this be repaired?

Most of the time, the tool simply needs a tune up. A tune up would consist of a cleaning and fresh lube applied, along with the installation of the appropriate o-ring kit and trigger valve assembly (TVA). These actions will greatly improve the cycle speed and energy of the tool. If a tune up does not solve the problem, some additional components should be checked: 1) piston stop 2) cylinder cap assembly worn where the head valve o-rings seat 3) cylinder sleeve worn 4) driver piston assembly -- check to see if the driver threads have loosened in the piston 5) air pressure too low -- check compressor level and performance