I have an intermittent engine problem. Sometimes the engine seems to lose power, like it's missing. Tonight I unplugged and reattatched all my spark plug wires and I reset my fuel pressure regulator from 4 to 6 psi and now the power is back. My fpr never seems to stay at 6. After I drive around I'll check it and it'll be up at 8 or sometimes its down around 4. Even when I set it to 6 at idle the gauge will jump around 5-6. Its a liquid filled gauge. Should the fpr gauge stay right on 6? Are these signs that my fuel pump is failing? I had the engine out recently and on the refire the fuel filter caught a lot of debris, so I changed that. Also, the fuel filter is after the fpr. If anyone has any ideas I'd love to hear them.