Ryan:

Dirty filters can give running problems, but usually don't decrease milage all that much, just power.

Change your fuel brand, diesel fuel isn't as consistant a product as gasoline is. I have found the local Phillips 66 to be horrible -- lots of smoke, no power, lousy milage -- while the local discount dealer is fine, as it Shell or Amoco/BP. It is entirely possible that the fuel you used gave you much less milage than normal, especially if you had more smoke!

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!