If it's big enough (torn boot between air meter horn and throttle body or really bad idle control valve hoses), the computer cannot compensate with enrichment and it will lope and stagger from lean mixture.

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!