there is a bad electrical connection at the fuel module.the pressure sensor is not the problem.it is only detecting the sudden drop in fuel pressure,You are only noticing a drop in rpm.the same it's causing the loosing of the fuel gauge reading.check the fuel tank electrical connector for signs of corrosion or a back up terminal or even melting of the plastic material due to overheating.test the wires with an ohm meter,should be no resistance.(across the connector,i mean.)if nothing is found,drop the tank and replace the complete fuel module.that is the plastic cup that is inside the gas tank and contents the pump,the level sensor and strainer filter.