Wow that is a quick reply. I have not tried Diesel Purge. I don't think that it is an injector knock because usually the injector knock it more pronounced at idle and diminishes with increased engine speed. I may be wrong, but I am willing to put in new injectors if that is a possible source of the noise. Thanks for the new idea to think about.

__________________
1993 300D 2.5 Turbo (blue/ blue tex)
1991 350SDL (White/ Gray leather)
1983 300TD Turbo 5-speed manual (Green/ Beige)
1985 300SD (Black/ Black Leather)
1985 300TD (White/ Green Tex)
1980 300SD (Astral Silver/ Black Leather)
1990 560SEL (White/ Gray Leather)
1993 300SD (Black/ Black Leather)
1967 200D (Green/ Beige Tex)
1969 300SEL 6.3 (Moss Green Metallic/ Green Leather)
1975 300D (Astral Silver/ Green Tex)
2001 Ford Excursion Diesel