Even on used and abused cars with many many miles, the tank screen can be completely fine unless it has been subject to bad fuel or conditions necessary for the production of algae. Personally, I wouldn't go thru the work of cleaning a tank screen without determining whether there was evidence of a problem there by either swapping the inlet and return lines in the engine compartment or setting up a separate fuel supply under the hood. Two minutes of effort could exclude the tank screen as the cause of the problem without requiring a bath in diesel fuel.

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13