Just because the pressure is 35psi does NOT necessarily mean the pump is bad. Several things can cause insufficient fuel pressure. A poor electrical connection anywhere in the circuit such as the fuse, ECM, fuel pump relay, fuel pump module, fuel pump motor, relay ground or pump ground. It could be a faulty or weak pump, or a fuel leak either internal or external. When it acts up, you need to have a fuel pressure tester connected to determine if the pump is running and what the pressure is, if it is holding pressure, and if the pump is capable of building sufficient pressure to satisfy the fuel pressure regulator.