Although your problem could be caused by a vacuum leak I think it is more likely caused by a breakdown in the ignition system (bad ignition wires and worn spark plugs). Visually inspect all of the hoses, listen for hissing at the mode switch (the switch that controls the a/c and heat) and check that they are all connected correctly. Play particular attention to the hoses in the front of the motor, it is easy to knock one loose without knowing it when working in that area. If the problem persists after checking the hoses do a complete tune-up replacing air, fuel, and oil filters, ignition cap and rotor, ignition wires, spark plugs. If there are enough miles on the car (30,000) replace the O2 sensor and adjust the valves. (It is also possible but unlikely that the air sensor plate is not centered or the plunger in the fuel mixture unit is sticking.) If this doesn't fix the problem then you have to take out the fuel injectors and have them tested and cleaned. Since you are a new owner unless you really know the history of the car it is best to start off with new parts. You should also pressure test the coling system to 15 psi for 15 min. Replace ALL of the hoses if any feel too hard or too soft or if any have any bulges. Flush the brake and clutch fluid replaceing with Castrol GTLMA DOT 4. David Teitelbaum vin 10757 --- In dmcnews@xxxx, ericp@xxxx wrote: > Hi Folks, > > I'm a newbie to owning a "D", and a newbie to your group. > As an electrical engineer I'm hoping maybe my experience can help > someone in those areas - but for now I'm the one looking for some > mechanical help. > > My D is having "Deceleration" problems. When cold or hot, it starts > fine, although the idle hunts slightly. The acceleration is smooth > and powerful, however on deceleration it "kicks" and feels very > choppy. > > I suspect a vacuum related problem, but have no real proof of that - > only that it mimicks the symptoms of a car from years before. > > Any suggestions before I seek out a local pro?