Vin:

You have a vacuum leak, most likely at the idle control valve. Those big rubber hoses get hard, shrink, and fit loose with age. All the rubber vac hoses on the engine are likely to be bad by now, I'd replace them all. The plastic lines are probably OK. If you have harsh tranny shifts and the defrost comes on when you accelerate, you definitely have a vac leak.

The vac leak means that when you open the throttle, no air goes down the fuel metering flap for a second, so there is no throttle response. If it then suddenly roars off, this is even more likely.

It's also possible that the throttle posistion sensor "pot" on the side of the throttle body is bad, too, so that you dont' get good enrichement on throttle opening. It can be replaced.

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!