We have a 1983 DMC with 84k miles on it, which we have refurbished. Since we started the engine, upon deceleration or light throttle the engine bucks and jerks. We have replaced fuel pump, filter, accumulator, injectors, distributor cap and rotor, ht leads, plugs,oxygen sensor, and injector seals. A Volvo specialist has set the mixture and the timing is at the prescribed 13 degrees BTDC. We have tried everything we know possible, and have checked and fixed every vacuum leak. The car accelerates smoothly, all 6 injectors deliver exactly the same amount of fuel, the frequency valve is operating, we have set the throttle switches correctly, the vacuum advance on the distributor is not sticking. Any ideas on what could be causing this? Nothing we have done has had any effect. We notice even with new injectors at low flow, the pattern is not a perfect cone on every one. Could it be that the new injectors are bad, and we are not getting perfect atomization at low flow?