Changed the fuel filter after almost 10K and observed something new. Apparently my dealer and others who have been changing the filter never really cleaned the bottom of the plastic canister which is not smooth but has several ribs which meet in the center. Anyhow, I changed the filter on a bright sunny day and observed a concretion of black brownish gooey tar had formed on the bottom and was almost up to the top of the ribs in a couple of places. This fine sediment was not gritty but almost clay like. Asphaltene particles that have deposited on the bottom of the housing? Anyways, a cup of unleaded and a toothbrush and a long screwdriver to gently scrape where the toothbrush couldn't reach and some swishing and the bottom of the housing was as new as the day it came off the Fleetguard assembly line!