We have completely rebuilt the original 6 cylinder engine and it runs well but there is an annoying noise coming from the fuel pump when the car idles, kind of clanking. The noise is coming from the fuel pump, we replaced it twice but the same issue remains. If one holds the fuel line to the pump the same throbbing can be felt. When the engine is in gear and using fuel the noise is gone but as soon as it idles it begins again. The fuel pump is an off the shelf replacement part from Auto Zone that does not have the canister type filter, we put in an inline filter to make up for this. Would I have better luck with an original type canister fuel pump? Is this issue something worse than just a noisy pump?