Rotten suction side fuel line, allows air in when the engine is running instead of sucking fuel out of the tank.

Made much worse by algae or crud in the tank screen, which on the Nissan is probably on the end of the pickup. Remove the fuel sender and pickup from the tank (may have to remove tank, it's probably on the top and not easily accessable installed), screen is obvious. Clean tank of crudded up.

Check fuel lines for cracks, since they are always under negative pressue, you don't get leaks out.

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!