Fuel pressure relief valves. The relief valve is located in the rear of the fuel rail. Nissan sells a complete fuel rail not the valve. When you accelerate heavy, the valve bypasses, the engine looses power [limp mode], there will be a P1272 code logged. To clear the code you shut down the engine. Restart and the code is clear. The next time you accelerate the valve will bypass again putting the engine in limp mode. The answer is a Fuel Rail Plug. It is a direct replacement part that works. This is an off road product.

Common rail fuel systems operate at extreme fuel pressure, only experienced persons should work on these systems. Do not under any circumstances loosen fuel components on a running engine. The fuel system holds residual pressure for several minutes after shut down. Only loosen parts 10 minutes after shutdown.  Do not touch or place body parts near running common rail fuel system pipes. Do not touch any leaks as you can be injected with diesel which is life threatening. 

YD25 fuel rail plug