Can a bad fuel pump make a knocking sound similar to a bad bearing? My 3.8 began losing power just after getting on plane a few days ago, then shortly thereafter developed a knock, sounding like a bad bearing. The timing is good, I've checked it running on fresh gas, it's not getting hot, and it has 50 lbs. of oil pressure at idle. All ignition parts are new, or very recent. Engine starts right up and idles very smoothly, but it has a very rythmic knock at idle that increases with speed. The outdrive is off the boat and the engine is ready to be lifted out, but before I take any covers off I'm going to remove the fuel pump and inspect it. Any comments?