Stalls on hard deceleration are almost always the idle control valve. This will be worse since by now the idle control valve hoses are rock hard and probably leaking.

I would clean the idle control valve and replace the hoses if not pliable (they won't be), and check for and repair any other vacuum leaks found.

If that doesn't cure the problem, it's time to look at the fuel system -- bad injectors will drive you nuts, so will an out of adjustment mixture (although this will probably be cured by fixing the vac leaks you surely have).

A bad OVP can cause this, as can a bad fuel pump relay. Both will cause problems while driving, though -- if the car intermittantly stalls while driving, as opposed to stoping hard, replace the fuel pump relay. If the OVP has a single fuse on it, replace that too, it's about time. You should also have the fuel pump current draw checked, as a bad fuel pump will damage the new fuel pump relay.

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!