1995 Honda Civic Rattle from the fuel filter?

I just bought this car not too long ago with no motor. I replaced the motor with a JDM engine and the car runs and drive great (although I checked the oil level today after about 800 miles of driving and it seems to be down ½ quart). My question is while sitting in the car at an idle there is a very noticeable rattle or clicking that almost sounds like a valve train noise. After listing to every surface of the engine and engine compartment if seems like the noise is coming from the fuel filter which is attached to the firewall and would make sense as to why its audible from inside the car. As soon as you start to move the car the noise goes away. I have also unbolted the fuel filter from the firewall and the noise goes away. Today I replaced the fuel filter again and no change. Any ideas?