I concur w/ 240DieselDog. Replace your spin-on and inline filters and see if that fixes the problem. After that, you'll have to start looking at the rest of the fuel system (ie, fuel pump).

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1973 280C
1977 280se (donor for the 280c)

'91 miata with mp45
2000 subaru wagon 5-speed

Deceased:
1971 220 Diesel 420k

Former:
81 240d 670k - retired
84 300D turbo 250k - sold
84 300TD turbo - gave to dad