Duramax P0087 Fuel Pressure CodeSo we see this in the shop weekly and also online all the time. Driving down the road or starting the truck up and pops with a P0087 code. We'll walk you through a quick tutorial on what it means, its likely causes, and fixes for that issue. The P0087 code is a fuel pressure code signaling the pressure is below spec. The sensor is located on the fuel rail, and this is what triggers the code to be thrown.